File: GEOTIFF.TXT Date: September 5, 1995 +---------------------------------------------------------------------+ GeoTIFF Format Specification GeoTIFF Revision 0.2 +---------------------------------------------------------------------+ Specification Version: 1.7 Last Modified: 13 July, 1995 Authors: Niles Ritter, Jet Propulsion Laboratory Cartographic Applications Group 4800 Oak Grove Dr. Pasadena, CA 91109 email:ndr@tazboy.jpl.nasa.gov Mike Ruth, SPOT Image Corp Product Development Group 1897 Preston White Dr. Reston, VA 22091 email:ruth@spot.com Acknowledgements: GeoTIFF Working Group: Mike Ruth, Niles Ritter, Ed Grissom, Brett Borup, George Galang, John Haller, Gary Stephenson, Steve Covington, Tim Nagy, Jamie Moyers, Jim Stickley, Joe Messina, Yves Somer. Additional advice from discussions with Tom Lane, Sam Leffler regarding TIFF implementations. Roger Lott, Fredrik Lundh, and Jarle Land provided valuable information regarding projections, projection code databases and geodetics. GeoTIFF Mailing list: Posting: geotiff@tazboy.jpl.nasa.gov Subscription: geotiff-request@tazboy.jpl.nasa.gov (send message "subscribe geotiff your-name-here"). Disclaimers and Notes for This Version: This proposal has not been approved by SPOT, JPL, or any other organization. This represents a proposal, which derives from many discussions between an international body of TIFF users and developers. The authors and their sponsors assume no liability for any special, incidental, indirect or consequences of any kind, or any damages whatsoever resulting from loss of use, data or profits, whether or not advised of the possibility of damage, and on any theory of of liability, arising out of or in connectionwith the use of this specification. Copyright Portions of this specification are copyrighted by Niles Ritter and Mike Ruth. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct or commercial advantage and this copyright notice appears. Licenses and Trademarks Aldus and Adobe are registered trademarks, and TIFF is a registered trademark of Aldus Corp, now owned by Adobe. SPOT Image, ESRI, ERDAS, ARC/Info, Intergraph and Softdesk are registered trademarks. Concurrence The following members of the GeoTIFF working group have reviewed and approved of this revision. Name Organization Representing -------------------- ----------------------- ------------ Niles Ritter Jet Propulsion Labs JPL Carto Group Mike Ruth SPOT Image Corp (USA) SPOT Image Corp (USA) +--------------------------------------------------------------------+ 1 Introduction +--------------------------------------------------------------------+ +----------------------------------+ 1.1 About this Specification This is a description of a proposal to specify the content and structure of a group of industry-standard tag sets for the management of georeference or geocoded raster imagery using Aldus-Adobe's public domain Tagged-Image File Format (TIFF). This specification closely follows the organization and structure of the TIFF specification document. +----------------------------------+ 1.1.1 Background TIFF has emerged as one of the world's most popular raster file formats. But TIFF remains limited in cartographic applications, since no publicly available, stable structure for conveying geographic information presently exists in the public domain. Several private solutions exist for recording cartographic information in TIFF tags. Intergraph has a mature and sophisticated geotie tag implementation, but this remains within the private TIFF tagset registered exclusively to Intergraph. Other companies (such as ESRI, and Island Graphics) have geographic solutions which are also proprietary or limited by specific application to their software's architecture. Many GIS companies, raster data providers, and their clients have requested that the companies concerned with delivery and exploitation of raster geographic imagery develop a publicly available, platform interoperable standard for the support of geographic TIFF imagery. Such TIFF imagery would originate from satellite imaging platforms, aerial platforms, scans of aerial photography or paper maps, or as a result of geographic analysis. TIFF images which were supported by the public "geotie" tagset would be able to be read and positioned correctly in any GIS or digital mapping system which supports the "GeoTIFF" standard, as proposed in this document. The savings to the users and providers of raster data and exploitation softwares are potentially significant. With a platform interoperable GeoTIFF file, companies could stop spending excessive development resource in support of any and all proprietary formats which are invented. Data providers may be able to produce off-the-shelf imagery products which can be delivered in the "generic" TIFF format quickly and possibly at lower cost. End-users will have the advantage of developed software that exploits the GeoTIFF tags transparently. Most importantly, the same raster TIFF image which can be read and modified in one GIS environment may be equally exploitable in another GIS environment without requiring any file duplication or import/export operation. +----------------------------------+ 1.1.2 History The initial efforts to define a TIFF "geotie" specification began under the leadership of Ed Grissom at Intergraph,and others in the early 1990's. In 1994 a formal GeoTIFF mailing-list was created and maintained by Niles Ritter at JPL, which quickly grew to over 140 subscribers from government and industry. The purpose of the list is to discuss common goals and interests in developing an industry-wide GeoTIFF standard, and culminated in a conference in March of 1995 hosted by SPOT Image, with representatives from USGS, Intergraph, ESRI, ERDAS, SoftDesk, MapInfo, NASA/JPL, and others, in which the current working proposal for GeoTIFF was outlined. The outline was condensed into a prerelease GeoTIFF specification document by Niles Ritter, and Mike Ruth of SPOT Image. Following discussions with Dr. Roger Lott of the European Petroleum Survey Group (EPSG), the GeoTIFF projection parametrization method was extensively modified, and brought into compatibility with both the POSC Epicentre model, and the Federal Geographic Data Committee (FGDC) metadata approaches. +----------------------------------+ 1.1.3 Scope The GeoTIFF spec defines a set of TIFF tags provided to describe all "Cartographic" information associated with TIFF imagery that originates from satellite imaging systems, scanned aerial photography, scanned maps, digital elevation models, or as a result of geographic analyses. Its aim is to allow means for tying a raster image to a known model space or map projection, and for describing those projections. GeoTIFF does not intend to become a replacement for existing geographic data interchange standards, such as the USGS SDTS standard or the FGDC metadata standard. Rather, it aims to augment an existing popular raster-data format to support georeferencing and geocoding information. The tags documented in this spec are to be considered completely orthogonal to the raster-data descriptions of the TIFF spec, and impose no restrictions on how the standard TIFF tags are to be interpreted, which color spaces or compression types are to be used, etc. +----------------------------------+ 1.1.4 Features GeoTIFF fully complies with the TIFF 6.0 specifications, and its extensions do not in any way go against the TIFF recommendations, nor do they limit the scope of raster data supported by TIFF. GeoTIFF uses a small set of reserved TIFF tags to store a broad range of georeferencing information, including UTM, US State Plane, National Grids, ARC, as well as the underlying projection types such as Transverse Mercator, Geographic, Lambert Conformal Conic, etc. No information is stored in private structures, IFD's or other mechanisms which would hide information from naive TIFF reading software. GeoTIFF uses a "MetaTag" (GeoKey) approach to encode dozens of information elements into just 6 tags, taking advantage of TIFF platform-independent data format representation to avoid cross-platform interchange difficulties. These keys are designed in a manner parallel to standard TIFF tags, and closely follow the TIFF discipline in their structure and layout. New keys may be defined as needs arise, within the current framework, and without requiring the allocation of new tags from Aldus/Adobe. GeoTIFF uses numerical codes to describe projection types, coordinate systems, datums, ellipsoids, etc. The projection, datums and ellipsoid codes are derived from the EPSG list compiled by the Petrotechnical Open Software Company (POSC), and mechanisms for adding further international projections,datums and ellipsoids has been established. The GeoTIFF information content is designed to be compatible with the data decomposition approach used by the National Spatial Data Infrastructure (NSDI) of the U.S. Federal Geographic Data Committee (FGDC). While GeoTIFF provides a robust framework for specifying a broad class of existing Projected coordinate systems, it is also fully extensible, permitting internal, private or proprietary information storage. However, since this standard arose from the need to avoid multiple proprietary encoding systems, use of private implementations is to be discouraged. +----------------------------------+ 1.2 Revision Notes This is the second (beta) release of GeoTIFF Revision 0.2, supporting the new EPSG 2.1 codes. +----------------------------------+ 1.2.1 Revision Nomenclature A Revision of GeoTIFF specifications will be denoted by two integers separated by a decimal, indicating the Major and Minor revision numbers. GeoTIFF stores most of its information using a "Key-Code" pairing system; the Major revision number will only be incremented when a substantial addition or modification is made to the list of information Keys, while the Minor Revision number permits incremental augmentation of the list of valid codes. +----------------------------------+ 1.2.2 New Features New EPSG 2.1 Codes installed. +----------------------------------+ 1.2.3 Clarifications o GeoTIFF-writers shall store the GeoKey entries in key-sorted order within the GeoKeyDirectoryTag. This is a change from preliminary discussions which permitted arbitrary order, and more closely follows the TIFF discipline. o The third value "ScaleZ" in ModelPixelScaleTag = (ScaleX, ScaleY, ScaleZ) shall by default be set to 0, not 1, as suggested in preliminary discussions. This is because most standard model spaces are 2-dimensional (flat), and therefore its vertical shape is independent of the pixel-value. o The code 32767 shall be used to imply "user-defined", rather than 16384. This avoids breaking up the reserved public GeoKey code space into two discontiguous ranges, 0-16383 and 16385-32767. o If a GeoKey is coded "undefined", then it is exactly that; no parameters should be provided (e.g. EllipsoidSemiMajorAxis, etc). To provide parameters for a non-coded attribute, use "user-defined". +----------------------------------+ 1.2.4 Organizational changes None. +----------------------------------+ 1.2.5 Changes in Requirements Changes to this preliminary revision: o South Oriented Gauss Conformal is now a distinct code. +----------------------------------+ 1.2.6 Agenda for Future Development A three-phase development of GeoTIFF approach is proposed in this document, which will be implemented with three Major Revisions: 0.x, 1.x and 2.x. Further revisions may occur as the need arises, though most will be in the form of incremental (minor) revisions. Revision 0.1, representing the first "Beta" revision implementation, was released in June 1995 and is subject to the first beta implementation in code. An incremental 0.2 revision has been made. Incremental 0.x changes may also occur, and lists of additional Keys for the next Major revision will be collected by the GeoTIFF mailing list. The goal is to make 0.x as close to the baseline requirements as possible. Revision 1.0, will be the first true "Baseline" revision, and is proposed to support well-documented, public, relatively simple Projected Coordinate Systems (PCS), including most commonly used and supported in the international public domains today, together with their underlying map-projection systems. Following the critiques of the 0.x Revision phase, the 1.0 Revision spec will be released in July 95 timeframe. As before, incremental 1.x augmentations to the "codes" list will be established, as well as discussions regarding the future "2.0" requirements. The Revision 2.0 phase is proposed to extend the capability of the GeoTIFF tagsets beyond PCS projections into more complex map projection geometries, including single-project, single-vendor, or proprietary cartographic solutions. TBD: Sounding Datums and related parameters for Digital Elevation Models (DEM's) and bathymetry -- Revision 2? +----------------------------------+ 1.3 Administration +----------------------------------+ 1.3.1 Information and Support: The most recent version of the GeoTIFF spec is available via anonymous FTP at: ftp://mtritter.jpl.nasa.gov/pub/tiff/geotiff/ and is mirrored at the USGS: ftp://ftpmcmc.cr.usgs.gov/release/geotiff/ Information and a hypertext version of the GeoTIFF spec is available via WWW at the following site: http://www-mipl.jpl.nasa.gov/~ndr/cartlab/geotiff/geotiff.html A mailing-list is currently active to discuss the on-going development of this standard. To subscribe to this list, send e-mail to: GeoTIFF-request@tazboy.jpl.nasa.gov with no subject and the body of the message reading: subscribe geotiff your-name-here To post inquiries directly to the list, send email to: geotiff@tazboy.jpl.nasa.gov +----------------------------------+ 1.3.2 Private Keys and Codes: As with TIFF, in GeoTIFF private "GeoKeys" and codes may be used, starting with 32768 and above. Unlike the TIFF spec, however, these private key-spaces will not be reserved, and are only to be used for private, internal purposes. +----------------------------------+ 1.3.3 Proposed Revisions to GeoTIFF Should a feature arise which is not currently supported, it should be formally proposed for addition to the GeoTIFF spec, through the official mailing-list. The current maintainer of the GeoTIFF specification is Niles Ritter, though this may change at a later time. Projection codes are maintained through EPSG/POSC, and a mechanism for change/additions will be established through the GeoTIFF mailing list. +--------------------------------------------------------------------+ 2 Baseline GeoTIFF +--------------------------------------------------------------------+ +----------------------------------+ 2.1 Notation This spec follows the notation remarks of the TIFF 6.0 spec, regarding "is", "shall", "should", and "may"; the first two indicate mandatory requirements, "should" indicates a strong recommendation, while "may" indicates an option. +----------------------------------+ 2.2 GeoTIFF Design Considerations Every effort has been made to adhere to the philosophy of TIFF data abstraction. The GeoTIFF tags conform to a hierarchical data structure of tags and keys, similar to the tags which have been implemented in the "basic" and "extended" TIFF tags already supported in TIFF Version 6 specification. The following are some points considered in the design of GeoTIFF: o Private binary structures, while permitted under the TIFF spec, are in general difficult to maintain, and are intrinsically platform- dependent. Whenever possible, information should be sorted into their intrinsic data-types, and placed into appropriately named tags. Also, implementors of TIFF readers would be more willing to honor a new tag specification if it does not require parsing novel binary structures. o Any Tag value which is to be used as a "keyword" switch or modifier should be a SHORT type, rather than an ASCII string. This avoids common mistakes of mis-spelling a keyword, as well as facilitating an implementation in code using the "switch/case"features of most languages. In general, scanning ASCII strings for keywords (CaseINSensitiVE?) is a hazardous (not to mention slower and more complex) operation. o True "Extensibility" strongly suggests that the Tags defined have a sufficiently abstract definition so that the same tag and its values may be used and interpreted in different ways as more complex information spaces are developed. For example, the old SubFileType tag (255) had to be obsoleted and replaced with a NewSubFileType tag, because images began appearing which could not fit into the narrowly defined classes for that Tag. Conversely, the YCbCrSubsampling Tag has taken on new meaning and importance as the JPEG compression standard for TIFF becomes finalized. +----------------------------------+ 2.3 GeoTIFF Software Requirements GeoTIFF requires support for all documented TIFF 6.0 tag data-types, and in particular requires the IEEE double-precision floating point "DOUBLE" type tag. Most of the parameters for georeferencing will not have sufficient accuracy with single-precision IEEE, nor with RATIONAL format storage. The only other alternative for storing high-precision values would be to encode as ASCII, but this does not conform to TIFF recommendations for data encoding. It is worth emphasizing here that the TIFF spec indicates that TIFF- compliant readers shall honor the 'byte-order' indicator, meaning that 4-byte integers from files created on opposite order machines will be swapped in software, and that 8-byte DOUBLE's will be 8-byte swapped. A GeoTIFF reader/writer, in addition to supporting the standard TIFF tag types, must also have an additional module which can parse the "Geokey" MetaTag information. A public-domain software package for performing this function will soon be available. +----------------------------------+ 2.4 GeoTIFF File and "Key" Structure This section describes the abstract file-format and "GeoKey" data storage mechanism used in GeoTIFF. Uses of this mechanism for implementing georeferencing and geocoding is detailed in section 2.6 and section 2.7. A GeoTIFF file is a TIFF 6.0 file, and inherits the file structure as described in the corresponding portion of the TIFF spec. All GeoTIFF specific information is encoded in several additional reserved TIFF tags, and contains no private Image File Directories (IFD's), binary structures or other private information invisible to standard TIFF readers. The number and type of parameters that would be required to describe most popular projection types would, if implemented as separate TIFF tags, likely require dozens or even hundred of tags, exhausting the limited resources of the TIFF tag-space. On the other hand, a private IFD, while providing thousands of free tags, is limited in that its tag- values are invisible to non-savvy TIFF readers (which don't know that the IFD_OFFSET tag value points to a private IFD). To avoid these problems, a GeoTIFF file stores projection parameters in a set of "Keys" which are virtually identical in function to a "Tag", but has one more level of abstraction above TIFF. Effectively, it is a sort of "Meta-Tag". A Key works with formatted tag-values of a TIFF file the way that a TIFF file deals with the raw bytes of a data file. Like a tag, a Key has an ID number ranging from 0 to 65535, but unlike TIFF tags, all key ID's are available for use in GeoTIFF parameter definitions. The Keys in GeoTIFF (also call "GeoKeys") are all referenced from the GeoKeyDirectoryTag, which defined as follows: GeoKeyDirectoryTag: Tag = 34735 (87AF.H) Type = SHORT (2-byte unsigned short) N = variable, >= 4 Alias: ProjectionInfoTag, CoordSystemInfoTag Owner: SPOT Image, Inc. This tag may be used to store the GeoKey Directory, which defines and references the "GeoKeys", as described below. The tag is an an array of unsigned SHORT values, which are primarily grouped into blocks of 4. The first 4 values are special, and contain GeoKey directory header information. The header values consist of the following information, in order: Header={KeyDirectoryVersion, KeyRevision, MinorRevision, NumberOfKeys} where "KeyDirectoryVersion" indicates the current version of Key implementation, and will only change if this Tag's Key structure is changed. (Similar to the TIFFVersion (42)). The current DirectoryVersion number is 1. This value will most likely never change, and may be used to ensure that this is a valid Key-implementation. "KeyRevision" indicates what revision of Key-Sets are used. "MinorRevision" indicates what set of Key-codes are used. The complete revision number is denoted . "NumberOfKeys" indicates how many Keys are defined by the rest of this Tag. This header is immediately followed by a collection of KeyEntry sets, each of which is also 4-SHORTS long. Each KeyEntry is modeled on the "TIFFEntry" format of the TIFF directory header, and is of the form: KeyEntry = { KeyID, TIFFTagLocation, Count, Value_Offset } where "KeyID" gives the key-ID value of the Key (identical in function to TIFF tag ID, but completely independent of TIFF tag-space), "TIFFTagLocation" indicates which TIFF tag contains the value(s) of the Key: if TIFFTagLocation is 0, then the value is SHORT, and is contained in the "Value_Offset" entry. Otherwise, the type (format) of the value is implied by the TIFF-Type of the tag containing the value. "Count" indicates the number of values in this key. "Value_Offset" Value_Offset indicates the index- offset *into* the TagArray indicated by TIFFTagLocation, if it is nonzero. If TIFFTagLocation=0, then Value_Offset contains the actual (SHORT) value of the Key, and Count=1 is implied. Note that the offset is not a byte-offset, but rather an index based on the natural data type of the specified tag array. Following the KeyEntry definitions, the KeyDirectory tag may also contain additional values. For example, if a Key requires multiple SHORT values, they shall be placed at the end of this tag, and the KeyEntry will set TIFFTagLocation=GeoKeyDirectoryTag, with the Value_Offset pointing to the location of the value(s). All key-values which are not of type SHORT are to be stored in one of the following two tags, based on their format: GeoDoubleParamsTag: Tag = 34736 (87BO.H) Type = DOUBLE (IEEE Double precision) N = variable Owner: SPOT Image, Inc. This tag is used to store all of the DOUBLE valued GeoKeys, referenced by the GeoKeyDirectoryTag. The meaning of any value of this double array is determined from the GeoKeyDirectoryTag reference pointing to it. FLOAT values should first be converted to DOUBLE and stored here. GeoAsciiParamsTag: Tag = 34737 (87B1.H) Type = ASCII Owner: SPOT Image, Inc. N = variable This tag is used to store all of the ASCII valued GeoKeys, referenced by the GeoKeyDirectoryTag. Since keys use offsets into tags, any special comments may be placed at the beginning of this tag. For the most part, the only keys that are ASCII valued are "Citation" keys, giving documentation and references for obscure projections, datums, etc. Note on ASCII Keys: Special handling is required for ASCII-valued keys. While it is true that TIFF 6.0 permits multiple NULL-delimited strings within a single ASCII tag, the secondary strings might not appear in the output of naive "tiffdump" programs. For this reason, the null delimiter of each ASCII Key value shall be converted to a "|" (pipe) character before being installed back into the ASCII holding tag, so that a dump of the tag will look like this. AsciiTag="first_value|second_value|etc...last_value|" A baseline GeoTIFF-reader must check for and convert the final "|" pipe character of a key back into a NULL before returning it to the client software. GeoKey Sort Order: In the TIFF spec it is required that TIFF tags be written out to the file in tag-ID sorted order. This is done to avoid forcing software to perform N-squared sort operations when reading and writing tags. To follow the TIFF philosophy, GeoTIFF-writers shall store the GeoKey entries in key-sorted order within the CoordSystemInfoTag. Example: GeoKeyDirectoryTag=( 1, 1, 2, 6, 1024, 0, 1, 2, 1026, 34737,12, 0, 2048, 0, 1, 32767, 2049, 34737,14, 12, 2050, 0, 1, 6, 2051, 34736, 1, 0 ) GeoDoubleParamsTag(34736)=(1.5) GeoAsciiParamsTag(34737)=("Custom File|My Geographic|") The first line indicates that this is a Version 1 GeoTIFF GeoKey directory, the keys are Rev. 1.2, and there are 6 Keys defined in this tag. The next line indicates that the first Key (ID=1024 = GTModelTypeGeoKey) has the value 2 (Geographic), explicitly placed in the entry list (since TIFFTagLocation=0). The next line indicates that the Key 1026 (the GTCitationGeoKey) is listed in the GeoAsciiParamsTag (34737) array, starting at offset 0 (the first in array), and running for 12 bytes and so has the value "Custom File" (the "|" is converted to a null delimiter at the end). Going further down the list, the Key 2051 (GeogLinearUnitSizeGeoKey) is located in the GeoDoubleParamsTag (34736), at offset 0 and has the value 1.5; the value of key 2049 (GeogCitationGeoKey) is "My Geographic". The TIFF layer handles all the problems of data structure, platform independence, format types, etc, by specifying byte-offsets, byte-order format and count, while the Key describes its key values at the TIFF level by specifying Tag number, array-index, and count. Since all TIFF information occurs in TIFF arrays of some sort, we have a robust method for storing anything in a Key that would occur in a Tag. With this Key-value approach, there are 65536 Keys which have all the flexibility of TIFF tag, with the added advantage that a TIFF dump will provide all the information that exists in the GeoTIFF implementation. This GeoKey mechanism will be used extensively in section 2.7, where the numerous parameters for defining Coordinate Systems and their underlying projections are defined. +----------------------------------+ 2.5 Coordinate Systems in GeoTIFF Geotiff has been designed so that standard map coordinate system definitions can be readily stored in a single registered TIFF tag. It has also been designed to allow the description of coordinate system definitions which are non-standard, and for the description of transformations between coordinate systems, through the use of three or four additional TIFF tags. However, in order for the information to be correctly exchanged between various clients and providers of GeoTIFF, it is important to establish a common system for describing map projections. In the TIFF/GeoTIFF framework, there are essentially three different spaces upon which coordinate systems may be defined. The spaces are: 1) The raster space (Image space) R, used to reference the pixel values in an image, 2) The Device space D, and 3) The Model space, M, used to reference points on the earth. In the sections that follow we shall discuss the relevance and use of each of these spaces, and their corresponding coordinate systems, from the standpoint of GeoTIFF. +----------------------------------+ 2.5.1 Device Space and GeoTIFF In standard TIFF 6.0 there are tags which relate raster space R with device space D, such as monitor, scanner or printer. The list of such tags consists of the following: ResolutionUnit (296) XResolution (282) YResolution (283) Orientation (274) XPosition (286) YPosition (287) In Geotiff, provision is made to identify earth-referenced coordinate systems (model space M) and to relate M space with R space. This provision is independent of and can co-exist with the relationship between raster and device spaces. To emphasize the distinction, this spec shall not refer to "X" and "Y" raster coordinates, but rather to raster space "J" (row) and "I" (column) coordinate variables instead, as defined in section 2.5.2.2. +----------------------------------+ 2.5.2 Raster Coordinate Systems +----------------------------------+ 2.5.2.1 Raster Data Raster data consists of spatially coherent, digitally stored numerical data, collected from sensors, scanners, or in other ways numerically derived. The manner in which this storage is implemented in a TIFF file is described in the standard TIFF specification. Raster data values, as read in from a file, are organized by software into two dimensional arrays, the indices of the arrays being used as coordinates. There may also be additional indices for multispectral data, but these indices do not refer to spatial coordinates but spectral, and so of not of concern here. Many different types of raster data may be georeferenced, and there may be subtle ways in which the nature of the data itself influences how the coordinate system (Raster Space) is defined for raster data. For example, pixel data derived from imaging devices and sensors represent aggregate values collected over a small, finite, geographic area, and so it is natural to define coordinate systems in which the pixel value is thought of as filling an area. On the other hand, digital elevations models may consist of discrete "postings", which may best be considered as point measurements at the vertices of a grid, and not in the interior of a cell. 2.5.2.2 Raster Space The choice of origin for raster space is not entirely arbitrary, and depends upon the nature of the data collected. Raster space coordinates shall be referred to by their pixel types, ie, as "PixelIsArea" or "PixelIsPoint". Note: For simplicity, both raster spaces documented below use a fixed pixel size and spacing of 1. Information regarding the visual representation of this data, such as pixels with non-unit aspect ratios, scales, orientations, etc, are best communicated with the TIFF 6.0 standard tags. +----------------------------------+ "PixelIsArea" Raster Space The "PixelIsArea" raster grid space R, which is the default, uses coordinates I and J, with (0,0) denoting the upper-left corner of the image, and increasing I to the right, increasing J down. The first pixel-value fills the square grid cell with the bounds: top-left = (0,0), bottom-right = (1,1) and so on; by extension this one-by-one grid cell is also referred to as a pixel. An N by M pixel image covers an are with the mathematically defined bounds (0,0),(N,M). (0,0) +---+---+-> I | * | * | +---+---+ Standard (PixelIsArea) TIFF Raster space R, | (1,1) (2,1) showing the areas (*) of several pixels. | J +----------------------------------+ "PixelIsPoint" Raster Space The PixelIsPoint raster grid space R uses the same coordinate axis names as used in PixelIsArea Raster space, with increasing I to the right, increasing J down. The first pixel-value however, is realized as a point value located at (0,0). An N by M pixel image consists of points which fill the mathematically defined bounds (0,0),(N-1,M-1). (0,0) (1,0) *-------*------> I | | | | PixelIsPoint TIFF Raster space R, *-------* showing the location (*) of several pixels. | (1,1) J If a point-pixel image were to be displayed on a display device with pixel cells having the same size as the raster spacing, then the upper- left corner of the displayed image would be located in raster space at (-0.5, -0.5). +----------------------------------+ 2.5.3 Model Coordinate Systems The following methods of describing spatial model locations (as opposed to raster) are recognized in Geotiff: Geocentric coordinates Geographic coordinates Projected coordinates Vertical coordinates Geographic, geocentric and projected coordinates are all imposed on models of the earth. To describe a location uniquely, a coordinate set must be referenced to an adequately defined coordinate system. If a coordinate system is from the Geotiff standard definitions, the only reference required is the standard coordinate system code/name. If the coordinate system is non-standard, it must be defined. The required definitions are described below. Projected coordinates, local grid coordinates, and (usually) geographical coordinates, form two dimensional horizontal coordinate systems (i.e., horizontal with respect to the earth's surface). Height is not part of these systems. To describe a position in three dimensions it is necessary to consider height as a second one-dimensional vertical coordinate system. To georeference an image in GeoTIFF, you must specify a Raster Space coordinate system, choose a horizontal model coordinate system, and a transformation between these two, as will be described in section 2.6 +----------------------------------+ 2.5.3.1 Geographic Coordinate Systems Geographic Coordinate Systems are those that relate angular latitude and longitude (and optionally geodetic height) to an actual point on the earth. The process by which this is accomplished is rather complex, and so we describe the components of the process in detail here. +----------------------------------+ Ellipsoidal Models of the Earth The geoid - the earth stripped of all topography - forms a reference surface for the earth. However, because it is related to the earth's gravity field, the geoid is a very complex surface; indeed, at a detailed level its description is not well known. The geoid is therefore not used in practical mapping. It has been found that an oblate ellipsoid (an ellipse rotated about its minor axis) is a good approximation to the geoid and therefore a good model of the earth. Many approximations exist: several hundred ellipsoids have been defined for scientific purposes and about 30 are in day to day use for mapping. The size and shape of these ellipsoids can be defined through two parameters. Geotiff requires one of these to be the semi-major axis (a), and the second to be either the inverse flattening (1/f) or the semi-minor axis (b). Historical models exist which use a spherical approximation; such models are not recommended for modern applications, but if needed the size of a model sphere may be defined by specifying identical values for the semimajor and semiminor axes; the inverse flattening cannot be used as it becomes infinite for perfect spheres. Other ellipsoid parameters needed for mapping applications, for example the square of the eccentricity, can easily be calculated by an application from the two defining parameters. Note that Geotiff uses the modern geodesy convention for the symbol (b) for the semi-minor axis. No provision is made for mapping other planets in which a tri-dimensional (triaxial) ellipsoid might be required, where (b) would represent the semi-median axis and (c) the semi-minor axis. Numeric codes for ellipsoids regularly used for earth-mapping are included in the Geotiff reference lists. +----------------------------------+ Latitude and Longitude The coordinate axes of the system refererencing points on an ellipsoid are called latitude and longitude. More precisely, geodetic latitude and longitude are required in this Geotiff standard. A discussion of the several other types of latitude and longitude is beyond the scope of this document as they are not required for conventional mapping. Latitude is defined to be the angle subtended with the ellipsoid's equatorial plane by a perpendicular through the surface of the ellipsoid from a point. Latitude is positive if north of the equator, negative if south. Longitude is defined to be the angle measured about the minor (polar) axis of the ellipsoid from a prime meridian (see below) to the meridian through a point, positive if east of the prime meridian and negative if west. Unlike latitude which has a natural origin at the equator, there is no feature on the ellipsoid which forms a natural origin for the measurement of longitude. The zero longitude can be any defined meridian. Historically, nations have used the meridian through their national astronomical observatories, giving rise to several prime meridians. By international convention, the meridian through Greenwich, England is the standard prime meridian. Longitude is only unambiguous if the longitude of its prime meridian relative to Greenwich is given. Prime meridians other than Greenwich which are sometimes used for earth mapping are included in the Geotiff reference lists. +----------------------------------+ Geodetic Datums As well as there being several ellipsoids in use to model the earth, any one particular ellipsoid can have its location and orientation relative to the earth defined in different ways. If the relationship between the ellipsoid and the earth is changed, then the geographical coordinates of a point will change. Conversely, for geographical coordinates to uniquely describe a location the relationship between the earth and the ellipsoid must be defined. This relationship is described by a geodetic datum. An exact geodetic definition of geodetic datums is beyond the current scope of Geotiff. However the Geotiff standard requires that the geodetic datum being utilized be identified by numerical code. If required, defining parameters for the geodetic datum can be included as a citation. +----------------------------------+ Defining Geographic Coordinate Systems In summary, geographic coordinates are only unique if qualified by the code of the geographic coordinate system to which they belong. A geographic coordinate system has two axes, latitude and longitude, which are only unambiguous when both of the related prime meridian and geodetic datum are given, and in turn the geodetic datum definition includes the definition of an ellipsoid. The Geotiff standard includes a list of frequently used geographic coordinate systems and their component ellipsoids, geodetic datums and prime meridians. Within the Geotiff standard a geographic coordinate system can be identified either by the code of a standard geographic coordinate system or by a user-defined system. The user is expected to provide geographic coordinate system code/name, geodetic datum code/name, ellipsoid code (if in standard) or ellipsoid name and two defining parameters (a) and either (1/f) or (b), and prime meridian code (if in standard) or name and longitude relative to Greenwich. +----------------------------------+ 2.5.3.2 Geocentric Coordinate Systems A geocentric coordinate system is a 3-dimensional coordinate system with its origin at or near the center of the earth and with 3 orthogonal axes. The Z-axis is in or parallel to the earth's axis of rotation (or to the axis around which the rotational axis precesses). The X-axis is in or parallel to the plane of the equator and passes through its intersection with the Greenwich meridian, and the Y-axis is in the plane of the equator forming a right-handed coordinate system with the X and Z axes. Geocentric coordinate systems are not frequently used for describing locations, but they are often utilized as an intermediate step when transforming between geographic coordinate systems. (Coordinate system transformations are described in section 2.6 below). In the Geotiff standard, a geocentric coordinate system can be identified, either through the geographic code (which in turn implies a datum), or through a user-defined name. +----------------------------------+ 2.5.3.3 Projected Coordinate Systems Although a geographical coordinate system is mathematically two dimensional, it describes a three dimensional object and cannot be represented on a plane surface without distortion. Map projections are transformations of geographical coordinates to plane coordinates in which the characteristics of the distortions are controlled. A map projection consists of a coordinate system transformation method and a set of defining parameters. A projected coordinate system (PCS) is a two dimensional (horizontal) coordinate set which, for a specific map projection, has a single and unambiguous transformation to a geographic coordinate system. In GeoTIFF PCS's are defined using the POSC/EPSG system, in which the PCS planar coordinate system, the Geographic coordinate system, and the transformation between them, are broken down into simpler logical components. Here are schematic formulas showing how the Projected Coordinate Systems and Geographic Coordinates Systems are encoded: Projected_CS = Geographic_CS + Projection Geographic_CS = Angular_Unit + Geodetic_Datum + Prime_Meridian Projection = Linear Unit + Coord_Transf_Method + CT_Parameters Coord_Transf_Method = { TransverseMercator | LambertCC | ...} CT_Parameters = {OriginLatitude + StandardParallel+...} (See also the Reference Parameters documentation in section 2.5.4). Notice that "Transverse Mercator" is not referred to as a "Projection", but rather as a "Coordinate Transformation Method"; in GeoTIFF, as in EPSG/POSC, the word "Projection" is reserved for particular, well- defined systems in which both the coordinate transformation method, its defining parameters, and their linear units are established. Several tens of coordinate transformation methods have been developed. Many are very similar and for practical purposes can be considered to give identical results. For example in the Geotiff standard Gauss-Kruger and Gauss-Boaga projection types are considered to be of the type Transverse Mercator. Geotiff includes a listing of commonly used projection defining parameters. Different algorithms require different defining parameters. A future version of Geotiff will include formulas for specific map projection algorithms recommended for use with listed projection parameters. To limit the magnitude of distortions of projected coordinate systems, the boundaries of usage are sometimes restricted. To cover more extensive areas, two or more projected coordinate systems may be required. In some cases many of the defining parameters of a set of projected coordinate systems will be held constant. The Geotiff standard does not impose a strict hierarchy onto such zoned systems such as US State Plane or UTM, but considers each zone to be a discrete projected coordinate system; the ProjectedCSTypeGeoKey code value alone is sufficient to identify the standard coordinate systems. Within the Geotiff standard a projected coordinate system can be identified either by the code of a standard projected coordinate system or by a user-defined system. User-define projected coordinate systems may be defined by defining the Geographic Coordinate System, the coordinate transformation method and its associated parameters, as well as the planar system's linear units. 2.5.3.4 Vertical Coordinate Systems Many uses of Geotiff will be limited to a two-dimensional, horizontal, description of location for which geographic coordinate systems and projected coordinate systems are adequate. If a three-dimensional description of location is required Geotiff allows this either through the use of a geocentric coordinate system or by defining a vertical coordinate system and using this together with a geographic or projected coordinate system. In general usage, elevations and depths are referenced to a surface at or close to the geoid. Through increasing use of satellite positioning systems the ellipsoid is increasingly being used as a vertical reference surface. The relationship between the geoid and an ellipsoid is in general not well known, but is required when coordinate system transformations are to be executed. +----------------------------------+ 2.5.4 Reference Parameters Most of the numerical coding systems and coordinate system definitions are based on the hierarchical system developed by EPSG/POSC. The complete set of EPSG tables used in GeoTIFF is available via FTP to ftp://ftpmcmc.cr.usgs.gov/release/geotiff/tables or: ftp://mtritter.jpl.nasa.gov/pub/geotiff/tables Appended below is the README.TXT file that accompanies the tables of defining parameters for those codes: +-----------------------------------+ | EPSG Geodesy Parameters | | version 2.1, 2nd June 1995. | +-----------------------------------+ The European Petroleum Survey Group (EPSG) has compiled and is distrubuting this set of parameters defining various geodetic and cartographic coordinate systems to encourage standardisation across the Exploration and Production segment of the oil industry. The data is included as reference data in the Geotiff data exchange specification, in Iris21 the Petroconsultants data model, and in Epicentre, the POSC data model. Parameters map directly to the POSC Epicentre model v2.0, except for data item codes which are included in the files for data management purposes. Geodetic datum parameters are embedded within the geographic coordinate system file. This has been done to ease parameter maintenance as there is a high correlation between geodetic datum names and geographic coordinate system names. The Projected Coordinate System v2.0 tabulation consists of systems associated with locally used projections. Systems utilising the popular UTM grid system have also been included. Criteria used for material in these lists include: - information must be in the public domain: "private" data is not included. - data must be in current use. - parameters are given to a precision consistent with coordinates being to a precision of one centimetre. The user assumes the entire risk as to the accuracy and the use of this data. The data may be copied and distributed subject to the following conditions: 1) All data must then be copied without modification and all pages must be included; 2) All components of this data set must be distributed together; 3) The data may not be distributed for profit by any third party; and 4) Acknowledgement to the original source must be given. INFORMATION PROVIDED IN THIS DOCUMENT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. Data is distributed on MS-DOS formatted diskette in comma- separated record format. Additional copies may be obtained from Jean-Patrick Girbig at the address below at a cost of US$100 to cover media and shipping, payment to be made in favour of Petroconsultants S.A at Union Banque Suisses, 1211 Geneve 11, Switzerland (compte number 403 458 60 K). The data is to be made available on a bulletin board shortly. Shipping List ------------- This data set consists of 8 files: PROJCS.CSV Tabulation of Projected Coordinate Systems to which map grid coordinates may be referenced. GEOGCS.CSV Tabulation of Geographic Coordinate Systems to which latitude and longitude coordinates may be referenced. This table includes the equivalent geocentric coordinate systems and also the geodetic datum, reference to which allows latitude and longitude or geocentric XYZ to uniquely describe a location on the earth. VERTCS.CSV Tabulation of Vertical Coordinate Systems to which heights or depths may be referenced. This table is currently in an early form. PROJ.CSV Tabulation of transformation methods and parameters through which Projected Coordinate Systems are defined and related to Geographic Coordinate Systems. ELLIPS.CSV Tabulation of reference ellipsoids upon which geodetic datums are based. PMERID.CSV Tabulation of prime meridians upon which geodetic datums are based. UNITS.CSV Tabulation of length units used in Projected and Vertical Coordinate Systems and angle units used in Geographic Coordinate Systems. README.TXT This file. The data files (.CSV) have a heirarchical structure: +---------------------------+ +----------------------------+ | VERTCS | | PROJCS | +---------------------------+ +----------------------------+ |Vertical Coordinate Systems| |Projected Coordinate Systems| +-------------+-------------+ +------------+---------------+ | | +--------+ | | | | +--------------------------+ | | | | | +-------------+---------------+ | | | GEOGCS | | | +-----------------------------+ | | |Geographic Coordinate Systems| | | |Geocentric Coordinate Systems| | | +-----------------------------+ | | | Geodetic Datums | | | +-------------+---------------+ | | | | | +--------+-------+ | | | | | +------+-----+ +------+-----+ +------+-------+ | | PROJ | | ELLIPS | | PMERID | | +------------+ +------------+ +--------------+ | | Projection | | Ellipsoid | |Prime Meridian| | | Parameters | | Parameters | | Parameters | | +------+-----+ +------+-----+ +------+-------+ | | | | +------------+-----------+-----+----------------+ | +-------------+------------+ | UNITS | +--------------------------+ | Linear and Angular Units | +--------------------------+ The parameter listings are "living documents" and will be updated by the EPSG from time to time. Any comment or suggestions for improvements should be directed to: Jean-Patrick Girbig, or Roger Lott, Manager Cartography, Head of Survey, Petroconsultants S.A., BP Exploration, PO Box 152, Uxbridge One, 24 Chemin de la Marie, Harefield Road, 1258 Perly-Geneva, Uxbridge, Switzerland. Middlesex UB8 1PD, England. Internet: lottrj@txpcap.hou.xwh.bp.com Requests for the inclusion of new data should include supporting documentation. Requests for changing existing data should include reference to both the name and code of the item. 10th June 1995. +---------------------------------------------------------------------+ 2.6 Coordinate Transformations The purpose of Geotiff is to allow the definitive identification of georeferenced locations within a raster dataset. This is generally accomplished through tying raster space coordinates to a model space coordinate system, when no further information is required. In the GeoTIFF nomenclature, "georeferencing" refers to tying raster space to a model space M, while "geocoding" refers to defining how the model space M assigns coordinates to points on the earth. The three tags defined below may be used for defining the relationship between R and M, and the relationship may be diagrammed as: ModelPixelScaleTag ModelTiepointTag R ------------ OR --------------> M (I,J,K) ModelTransformationTag (X,Y,Z) The next section describes these Baseline georeferencing tags in detail. +----------------------------------+ 2.6.1 GeoTIFF Tags for Coordinate Transformations For most common applications, the transformation between raster and model space may be defined with a set of raster-to-model tiepoints and scaling parameters. The following two tags may be used for this purpose: ModelTiepointTag: Tag = 33922 (8482.H) Type = DOUBLE (IEEE Double precision) N = 6*K, K = number of tiepoints Alias: GeoreferenceTag Owner: Intergraph This tag stores raster->model tiepoint pairs in the order ModelTiepointTag = (...,I,J,K, X,Y,Z...), where (I,J,K) is the point at location (I,J) in raster space with pixel- value K, and (X,Y,Z) is a vector in model space. In most cases the model space is only two-dimensional, in which case both K and Z should be set to zero; this third dimension is provided in anticipation of future support for 3D digital elevation models and vertical coordinate systems. A raster image may be georeferenced simply by specifying its location, size and orientation in the model coordinate space M. This may be done by specifying the location of three of the four bounding corner points. However, tiepoints are only to be considered exact at the points specified; thus defining such a set of bounding tiepoints does not imply that the model space locations of the interior of the image may be exactly computed by a linear interpolation of these tiepoints. However, since the relationship between the Raster space and the model space will often be an exact, affine transformation, this relationship can be defined using one set of tiepoints and the "ModelPixelScaleTag", described below, which gives the vertical and horizontal raster grid cell size, specified in model units. If possible, the first tiepoint placed in this tag shall be the one establishing the location of the point (0,0) in raster space. However, if this is not possible (for example, if (0,0) is goes to a part of model space in which the projection is ill-defined), then there is no particular order in which the tiepoints need be listed. For orthorectification or mosaicking applications a large number of tiepoints may be specified on a mesh over the raster image. However, the definition of associated grid interpolation methods is not in the scope of the current GeoTIFF spec. Remark: As mentioned in section 2.5.1, all GeoTIFF information is independent of the XPosition, YPosition, and Orientation tags of the standard TIFF 6.0 spec. The next two tags are optional tags provided for defining exact affine transformations between raster and model space; baseline GeoTIFF files may use either, but shall never use both within the same TIFF image directory. ModelPixelScaleTag: Tag = 33550 Type = DOUBLE (IEEE Double precision) N = 3 Owner: SoftDesk This tag may be used to specify the size of raster pixel spacing in the model space units, when the raster space can be embedded in the model space coordinate system without rotation, and consists of the following 3 values: ModelPixelScaleTag = (ScaleX, ScaleY, ScaleZ) where ScaleX and ScaleY give the horizontal and vertical spacing of raster pixels. The ScaleZ is primarily used to map the pixel value of a digital elevation model into the correct Z-scale, and so for most other purposes this value should be zero (since most model spaces are 2-D, with Z=0). A single tiepoint in the ModelTiepointTag, together with this tag, completely determine the relationship between raster and model space; thus they comprise the two tags which Baseline GeoTIFF files most often will use to place a raster image into a "standard position" in model space. Like the Tiepoint tag, this tag information is independent of the XPosition, YPosition, Resolution and Orientation tags of the standard TIFF 6.0 spec. However, simple reversals of orientation between raster and model space (e.g. horizontal or vertical flips) may be indicated by reversal of sign in the corresponding component of the ModelPixelScaleTag. GeoTIFF compliant readers must honor this sign- reversal convention. This tag must not be used if the raster image requires rotation or shearing to place it into the standard model space. In such cases the transformation shall be defined with the more general ModelTransformationTag, defined below. ModelTransformationTag Tag = 33920 (8480.H) Type = DOUBLE N = 16 Owner: Intergraph This tag may be used to specify the transformation matrix between the raster space (and its dependent pixel-value space) and the (possibly 3D) model space. If specified, the tag shall have the following organization: ModelTransformationTag = (a,b,c,d,e....m,n,o,p). where model image coords = matrix * coords |- -| |- -| |- -| | X | | a b c d | | I | | | | | | | | Y | | e f g h | | J | | | = | | | | | Z | | i j k l | | K | | | | | | | | 1 | | m n o p | | 1 | |- -| |- -| |- -| By convention, and without loss of generality, the following parameters are currently hard-coded and will always be the same (but must be specified nonetheless): m = n = o = 0, p = 1. For Baseline GeoTIFF, the model space is always 2-D, and so the matrix will have the more limited form: |- -| |- -| |- -| | X | | a b 0 d | | I | | | | | | | | Y | | e f 0 h | | J | | | = | | | | | Z | | 0 0 0 0 | | K | | | | | | | | 1 | | 0 0 0 1 | | 1 | |- -| |- -| |- -| Values "d" and "h" will often be used to represent translations in X and Y, and so will not necessarily be zero. All 16 values should be specified, in all cases. Only the raster-to-model transformation is defined; if the inverse transformation is required it must be computed by the client, to the desired accuracy. This matrix tag should not be used if the ModelTiepointTag and the ModelPixelScaleTag are already defined. If only a single tiepoint (I,J,K,X,Y,Z) is specified, and the ModelPixelScale = (Sx, Sy, Sz) is specified, then the corresponding transformation matrix may be computed from them as: |- -| | Sx 0.0 0.0 Tx | | | Tx = X - I/Sx | 0.0 -Sy 0.0 Ty | Ty = Y + J/Sy | | Tz = Z - K/Sz (if not 0) | 0.0 0.0 Sz Tz | | | | 0.0 0.0 0.0 1.0 | |- -| where the -Sy is due the reversal of direction from J increasing- down in raster space to Y increasing-up in model space. Like the Tiepoint tag, this tag information is independent of the XPosition, YPosition, and Orientation tags of the standard TIFF 6.0 spec. +----------------------------------+ 2.6.2 Cookbook for Defining Transformations Here is a 4-step guide to producing a set of Baseline GeoTIFF tags for defining coordinate transformation information of a raster dataset. Step 1: Establish the Raster Space coordinate system used: RasterPixelIsArea or RasterPixelIsPoint. Step 2: Establish/define the model space Type in which the image is to be georeferenced. Usually this will be a Projected Coordinate system (PCS). If you are geocoding this data set, then the model space is defined to be the corresponding geographic, geocentric or Projected coordinate system (skip to the "Cookbook" section 2.7.3 first to do determine this). Step 3: Identify the nature of the transformations needed to tie the raster data down to the model space coordinate system: Case 1: The model-location of a raster point (x,y) is known, but not the scale or orientations: Use the ModelTiepointTag to define the (X,Y,Z) coordinates of the known raster point. Case 2: The location of three non-collinear raster points are known exactly, but the linearity of the transformation is not known. Use the ModelTiepointTag to define the (X,Y,Z) coordinates of all three known raster points. Do not compute or define the ModelPixelScale or ModelTransformation tag. Case 3: The position and scale of the data is known exactly, and no rotation or shearing is needed to fit into the model space. Use the ModelTiepointTag to define the (X,Y,Z) coordinates of the known raster point, and the ModelPixelScaleTag to specify the scale. Case 4: The raster data requires rotation and/or lateral shearing to fit into the defined model space: Use the ModelTransformation matrix to define the transformation. Case 5: The raster data cannot be fit into the model space with a simple affine transformation (rubber-sheeting required). Use only the ModelTiepoint tag, and specify as many tiepoints as your application requires. Note, however, that this is not a Baseline GeoTIFF implementation, and should not be used for interchange; it is recommended that the image be geometrically rectified first, and put into a standard projected coordinate system. Step 4: Install the defined tag values in the TIFF file and close it. +----------------------------------+ 2.7 Geocoding Raster Data +----------------------------------+ 2.7.1 General Approach A geocoded image is a georeferenced image as described in section 2.6, which also specifies a model space coordinate system (CS) between the model space M (to which the raster space has been tied) and the earth. The relationship can be diagrammed, including the associated TIFF tags, as follows: ModelPixelScaleTag ModelTiepointTag GeoKeyDirectoryTag CS R -------- OR ---------------> M --------- AND -----------> Earth ModelTransformationTag GeoDoubleParamsTag GeoAsciiParamsTag The geocoding coordinate system is defined by the GeoKeyDirectoryTag, while the Georeferencing information (T) is defined by the ModelTiepointTag and the ModelPixelScale, or ModelTransformationTag. Since these two systems are independent of each other, the tags used to store the parameters are separated from each other in the GeoTIFF file to emphasize the orthogonality. +----------------------------------+ 2.7.2 GeoTIFF GeoKeys for Geocoding As mentioned above, all information regarding the Model Coordinate System used in the raster data is referenced from the GeoKeyDirectoryTag, which stores all of the GeoKey entries. In the Appendix, section 6.2 summarizes all of the GeoKeys defined for baseline GeoTIFF, and their corresponding codes are documented in section 6.3. Only the Keys themselves are documented here. +----------------------------------+ Common Features +----------------------------------+ Public and Private Key and Code Ranges GeoTIFF GeoKey ID's may take any value between 0 and 65535. Following TIFF general approach, the GeoKey ID's from 32768 and above are available for private implementations. However, no registry will be established for these keys or codes, so developers are warned to use them at their own risk. The Key ID's from 0 to 32767 are reserved for use by the official GeoTIFF spec, and are broken down into the following sub-domains: [ 0, 1023] Reserved [ 1024, 2047] GeoTIFF Configuration Keys [ 2048, 3071] Geographic/Geocentric CS Parameter Keys [ 3072, 4095] Projected CS Parameter Keys [ 4096, 5119] Vertical CS Parameter Keys [ 5120, 32767] Reserved [32768, 65535] Private use GeoKey codes, like keys and tags, also range from 0 to 65535. Following the TIFF approach, all codes from 32768 and above are available for private user implementation. There will be no registry for these codes, however, and so developers must be sure that these tags will only be used internally. Use private codes at your own risk. The codes from 0 to 32767 for all public GeoKeys are reserved by this GeoTIFF specification. Common Public Code Values For consistency, several key codes have the same meaning in all implemented GeoKeys possessing a SHORT numerical coding system: 0 = undefined 32767 = user-defined The "undefined" code means that this parameter is intentionally omitted, for whatever reason. For example, the datum used for a given map may be unknown, or the accuracy of a aerial photo is so low that to specify a particular datum would imply a higher accuracy than is in the data. The "user-defined" code means that a feature is not among the standard list, and is being explicitly defined. In cases where this is meaningful, Geokey parameters have been supplied for the user to define this feature. "User-Defined" requirements: In each section below a specification of the additional GeoKeys required for the "user-defined" option is given. In all cases the corresponding "Citation" key is strongly recommended, as per the FGDC Metadata standard regarding "local" types. +----------------------------------+ GeoTIFF Configuration GeoKeys +----------------------------------+ These keys are to be used to establish the general configuration of this file's coordinate system, including the types of raster coordinate systems, model coordinate systems, and citations if any. +---------------------------------------------------------------------+ GTModelTypeGeoKey Key ID = 1024 Type: SHORT (code) Values: Section 6.3.1.1 Codes This GeoKey defines the general type of model Coordinate system used, and to which the raster space will be transformed:unknown, Geocentric (rarely used), Geographic, Projected Coordinate System, or user-defined. If the coordinate system is a PCS, then only the PCS code need be specified. If the coordinate system does not fit into one of the standard registered PCS'S, but it uses one of the standard projections and datums, then its should be documented as a PCS model with "user- defined" type, requiring the specification of projection parameters, etc. GeoKey requirements for User-Defined Model Type (not advisable): GTCitationGeoKey +---------------------------------------------------------------------+ GTRasterTypeGeoKey Key ID = 1025 Type = Section 6.3.1.2 codes This establishes the Raster Space coordinate system used; there are currently only two, namely RasterPixelIsPoint and RasterPixelIsArea. No user-defined raster spaces are currently supported. For variance in imaging display parameters, such as pixel aspect-ratios, use the standard TIFF 6.0 device-space tags instead. +---------------------------------------------------------------------+ GTCitationGeoKey Key ID = 1026 Type = ASCII As with all the "Citation" GeoKeys, this is provided to give an ASCII reference to published documentation on the overall configuration of this GeoTIFF file. +---------------------------------------------------------------------+ +----------------------------------+ Geographic CS Parameter GeoKeys +----------------------------------+ +---------------------------------------------------------------------+ In general, the geographic coordinate system used will be implied by the projected coordinate system code. If however, this is a user-defined PCS, or the ModelType was chosen to be Geographic, then the system must be explicitly defined here, using the Horizontal datum code. +---------------------------------------------------------------------+ GeographicTypeGeoKey Key ID = 2048 Type = SHORT (code) Values = Section 6.3.2.1 Codes This key may be used to specify the code for the geographic coordinate system used to map lat-long to a specific ellipsoid over the earth. GeoKey Requirements for User-Defined geographic CS: GeogCitationGeoKey GeogGeodeticDatumGeoKey GeogAngularUnitsGeoKey (if not degrees) GeogPrimeMeridianGeoKey (if not Greenwich) +---------------------------------------------------------------------+ GeogCitationGeoKey Key ID = 2049 Type = ASCII Values = text General citation and reference for all Geographic CS parameters. +---------------------------------------------------------------------+ GeogGeodeticDatumGeoKey Key ID = 2050 Type = SHORT (code) Values = Section 6.3.2.2 Codes This key may be used to specify the horizontal datum, defining the size, position and orientation of the reference ellipsoid used in user-defined geographic coordinate systems. GeoKey Requirements for User-Defined Horizontal Datum: GeogCitationGeoKey GeogEllipsoidGeoKey +---------------------------------------------------------------------+ GeogPrimeMeridianGeoKey Key ID = 2051 Type = SHORT (code) Units: Section 6.3.2.4 code Allows specification of the location of the Prime meridian for user- defined geographic coordinate systems. The default standard is Greenwich, England. +---------------------------------------------------------------------+ GeogLinearUnitsGeoKey Key ID = 2052 Type = DOUBLE Values: Section 6.3.1.3 Codes Allows the definition of geocentric CS linear units for user-defined GCS. +---------------------------------------------------------------------+ GeogLinearUnitSizeGeoKey Key ID = 2053 Type = DOUBLE Units: meters Allows the definition of user-defined linear geocentric units, as measured in meters. +---------------------------------------------------------------------+ GeogAngularUnitsGeoKey Key ID = 2054 Type = SHORT (code) Values = Section 6.3.1.4 Codes This key may be used to specify the angular units of measurement used in user-defined geographic coordinate system. GeoKey Requirements for "user-defined" units: GeogCitationGeoKey GeogAngularUnitSizeGeoKey +---------------------------------------------------------------------+ GeogAngularUnitSizeGeoKey Key ID = 2055 Type = DOUBLE Units: radians Allows the definition of user-defined angular geographic units, as measured in radians. +---------------------------------------------------------------------+ GeogEllipsoidGeoKey Key ID = 2056 Type = SHORT (code) Values = Section 6.3.2.3 Codes This key may be used to specify the coded ellipsoid used in the geodetic datum of the Geographic Coordinate System. GeoKey Requirements for User-Defined Ellipsoid: GeogCitationGeoKey [GeogSemiMajorAxisGeoKey, [GeogSemiMinorAxisGeoKey | GeogInvFlatteningGeoKey] ] +---------------------------------------------------------------------+ GeogSemiMajorAxisGeoKey Key ID = 2057 Type = DOUBLE Units: Geocentric CS Linear Units Allows the specification of user-defined Ellipsoid Semi-Major Axis (a). +---------------------------------------------------------------------+ GeogSemiMinorAxisGeoKey Key ID = 2058 Type = DOUBLE Units: Geocentric CS Linear Units Allows the specification of user-defined Ellipsoid Semi-Minor Axis (b). +---------------------------------------------------------------------+ GeogInvFlatteningGeoKey Key ID = 2059 Type = DOUBLE Units: none. Allows the specification of the inverse of user-defined Ellipsoid's flattening parameter (f). The eccentricity-squared e^2 of the ellipsoid is related to the non-inverted f by: e^2 = 2*f - f^2 Note: if the ellipsoid is spherical the inverse-flattening becomes infinite; use the GeogSemiMinorAxisGeoKey instead, and set it equal to the semi-major axis length. +---------------------------------------------------------------------+ GeogAzimuthUnitsGeoKey Key ID = 2060 Type = SHORT (code) Values = Section 6.3.1.4 Codes This key may be used to specify the angular units of measurement used to defining azimuths, in geographic coordinate systems. These may be used for defining azimuthal parameters for some projection algorithms, and may not necessarily be the same angular units used for lat-long. +---------------------------------------------------------------------+ GeogPrimeMeridianLongGeoKey Key ID = 2061 Type = DOUBLE Units = GeogAngularUnits This key allows definition of user-defined Prime Meridians, the location of which is defined by its longitude relative to Greenwich. +---------------------------------------------------------------------+ +----------------------------------+ Projected CS Parameter GeoKeys +----------------------------------+ The PCS range of GeoKeys includes the projection and coordinate transformation keys as well. The projection keys are included in this block since they can only be used to define projected coordinate systems. +---------------------------------------------------------------------+ ProjectedCSTypeGeoKey Key ID = 3072 Type = SHORT (codes) Values: Section 6.3.3.1 codes This code is provided to specify the projected coordinate system. GeoKey requirements for "user-defined" PCS families: PCSCitationGeoKey ProjectionGeoKey +---------------------------------------------------------------------+ PCSCitationGeoKey Key ID = 3073 Type = ASCII As with all the "Citation" GeoKeys, this is provided to give an ASCII reference to published documentation on the Projected Coordinate System particularly if this is a "user-defined" PCS. +---------------------------------------------------------------------+ +----------------------------------+ Projection Definition GeoKeys +----------------------------------+ +---------------------------------------------------------------------+ With the exception of the first two keys, these are mostly projection- specific parameters, and only a few will be required for any particular projection type. Projected coordinate systems automatically imply a specific projection type, as well as specific parameters for that projection, and so the keys below will only be necessary for user- defined projected coordinate systems. +---------------------------------------------------------------------+ ProjectionGeoKey Key ID = 3074 Type = SHORT (code) Values: Section 6.3.3.2 codes Allows specification of the coded projection used. Note: this does not include the definition of the corresponding Geographic Coordinate System to which the projected CS is related; only the projection is defined here. GeoKeys Required for "user-defined" Projections: PCSCitationGeoKey ProjCoordTransGeoKey ProjLinearUnitsGeoKey (additional parameters depending on ProjCoordTransGeoKey). +---------------------------------------------------------------------+ ProjCoordTransGeoKey Key ID = 3075 Type = SHORT (code) Values: Section 6.3.3.3 codes Allows specification of the coordinate transformation method used. Note: this does not include the definition of the corresponding Geographic Coordinate System to which the projected CS is related; only the transformation method is defined here. GeoKeys Required for "user-defined" Coordinate Transformations: PCSCitationGeoKey Now continue on to define the Geographic CS, below. case GEOCENTRIC: case GEOGRAPHIC: Check the list of standard GCS's and use the corresponding code. To use a code both the Datum, Prime Meridian, and angular units must match those of the code. Store in: GeographicTypeGeoKey and skip to Step 4. If none of the coded GCS's match exactly, then this is a user-defined GCS. Check the list of standard datums, Prime Meridians, and angular units to define your system. Store in: GeogGeodeticDatumGeoKey, GeogAngularUnitsGeoKey, GeogPrimeMeridianGeoKey and skip to Step 4. If none of the datums match your system, you have a user-defined datum, which is an odd system, indeed. Use the GeogEllipsoidGeoKey to select the appropriate ellipsoid or use the GeogSemiMajorAxisGeoKey, GeogInvFlatteningGeoKey to define, and give a reference using the GeogCitationGeoKey. Store in: GeogEllipsoidGeoKey, etc. and go to Step 4. Step 4: Install the GeoKeys/codes into the GeoKeyDirectoryTag, and the DOUBLE and ASCII key values into the corresponding value-tags. Step 5: Having completely defined the Raster & Model coordinate system, go to Cookbook section 2.6.2 and use the Georeferencing Tags to tie the raster image down onto the Model space. +----------------------------------+ 3 Examples +----------------------------------+ Here are some examples of how GeoTIFF may be implemented at the Tag and GeoKey level, following the general "Cookbook" approach above. +----------------------------------+ 3.1 Common Examples +----------------------------------+ 3.1.1. UTM Projected Aerial Photo We have an aerial photo which has been orthorectified and resampled to a UTM grid, zone 60, using WGS84 datum; the coordinates of the upper-left corner of the image is are given in easting/northing, as 350807.4m, 5316081.3m. The scanned map pixel scale is 100 meters/pixels (the actual dpi scanning ratio is irrelevant). ModelTiepointTag = (0, 0, 0, 350807.4, 5316081.3, 0.0) ModelPixelScaleTag = (100.0, 100.0, 0.0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 1 (ModelTypeProjected) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) ProjectedCSTypeGeoKey = 32660 (PCS_WGS84_UTM_zone_60N) PCSCitationGeoKey = "UTM Zone 60 N with WGS84" Notes: 1) We did not need to specify the GCS lat-long, since the PCS_WGS84_UTM_zone_60N codes implies particular GCS and units already (WGS_84 and meters). The citation was added just for documentation. 2) The "GeoKeyDirectoryTag" is expressed using the "GeoKey" structure defined above. At the TIFF level the tags look like this: GeoKeyDirectoryTag=( 1, 0, 1, 4, 1024, 0, 1, 1, 1025, 0, 1, 1, 3072, 0, 1, 32660, 3073, 34737, 25, 0 ) GeoAsciiParamsTag(34737)=("UTM Zone 60 N with WGS84|") For the rest of these examples we will only show the GeoKey-level dump, with the understanding that the actual TIFF-level tag representation can be determined from the documentation. +----------------------------------+ 3.1.2. Standard State Plane We have a USGS State Plane Map of Texas, Central Zone, using NAD83, correctly oriented. The map resolution is 1000 meters/pixel, at origin. There is a grid intersection line in the image at pixel location (50,100), and corresponds to the projected coordinate system easting/northing of (949465.0, 3070309.1). ModelTiepointTag = ( 50, 100, 0, 949465.0, 3070309.1, 0) ModelPixelScaleTag = (1000, 1000, 0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 1 (ModelTypeProjected) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) ProjectedCSTypeGeoKey = 32139 (PCS_NAD83_Texas_Central) Notice that in this case, since the PCS is a standard code, we do not need to define the GCS, datum, etc, since those are implied by the PCS code. Also, since this is NAD83, meters are used rather than US Survey feet (as in NAD 27). +----------------------------------+ 3.1.3. Lambert Conformal Conic Aeronautical Chart We have a 500 x 500 scanned aeronautical chart of Seattle, WA, using Lambert Conformal Conic projection, correctly oriented. The central meridian is at 120 degrees west. The map resolution is 1000 meters/pixel, at origin, and uses NAD27 datum. The standard parallels of the projection are at 41d20m N and 48d40m N. The latitude of the origin is at 45 degrees North, and occurs in the image at the raster coordinates (80,100). The origin is given a false easting and northing of 200000m, 1500000m. ModelTiepointTag = ( 80, 100, 0, 200000, 1500000, 0) ModelPixelScaleTag = (1000, 1000, 0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 1 (ModelTypeProjected) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) GeographicTypeGeoKey = 4267 (GCS_NAD27) ProjectedCSTypeGeoKey = 32767 (user-defined) ProjectionGeoKey = 32767 (user-defined) ProjLinearUnitsGeoKey = 1 (Linear_Meter) ProjCoordTransGeoKey = 8 (CT_LambertConfConic) ProjStdParallelGeoKey = 41.333 ProjStdParallel2GeoKey = 48.666 ProjCenterLongGeoKey =-120.0 ProjOriginLatGeoKey = 45.0 ProjFalseEastingGeoKey, = 200000.0 ProjFalseNorthingGeoKey, = 1500000.0 Notice that the Tiepoint takes the false easting and northing into account when tying the raster point (50,100) to the projection origin. +--------------------------------------------------------------------+ 3.1.3. DMA ADRG Raster Graphic Map The U.S. Defense Mapping Agency produces ARC digitized raster graphics datasets by scanning maps and geometrically resampling them into an equirectangular projection, so that they may be directly indexed with WGS84 geographic coordinates. The scale for one map is 0.2 degrees per pixel horizontally, 0.1 degrees per pixel vertically. If stored in a GeoTIFF file it contains the following information: ModelTiepointTag=(0.0, 0.0, 0.0, -120.0, 32.0, 0.0) ModelPixelScale = (0.2, 0.1, 0.0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 2 (ModelTypeGeographic) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) GeographicTypeGeoKey = 4326 (GCS_WGS_84) +----------------------------------+ 3.2 Less Common Examples +----------------------------------+ 3.2.1. Unrectified Aerial photo, known tiepoints, in degrees. We have an aerial photo, and know only the WGS84 GPS location of several points in the scene: the upper left corner is 120 degrees West, 32 degrees North, the lower-left corner is at 120 degrees West, 30 degrees 20 minutes North, and the lower-right hand corner of the image is at 116 degrees 40 minutes West, 30 degrees 20 minutes North. The photo is not geometrically corrected, however, and the complete projection is therefore not known. ModelTiepointTag=( 0.0, 0.0, 0.0, -120.0, 32.0, 0.0, 0.0, 1000.0, 0.0, -120.0, 30.33333, 0.0, 1000.0, 1000.0, 0.0, -116.6666667, 30.33333, 0.0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 1 (ModelTypeGeographic) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) GeographicTypeGeoKey = 4326 (GCS_WGS_84) Remark: Since we have not specified the ModelPixelScaleTag, clients reading this GeoTIFF file are not permitted to infer that there is a simple linear relationship between the raster data and the geographic model coordinate space. The only points that are know to be exact are the ones specified in the tiepoint tag. +----------------------------------+ 3.2.2. Rotated Scanned Map We have a scanned standard British National Grid, covering the 100km grid zone NZ. Consulting documentation for BNG we find that the southwest corner of the NZ zone has an easting,northing of 400000m, 500000m, relative to the BNG standard false origin. This scanned map has a resolution of 100 meter pixels, and was rotated 90 degrees to fit onto the scanner, so that the southwest corner is now the northwest corner. In this case we must use the ModelTransformation tag rather than the tiepoint/scale pair to map the raster data into model space: ModelTransformationTag = ( 0, 100.0, 0, 400000.0, 100.0, 0, 0, 500000.0, 0, 0, 0, 0, 0, 0, 0, 1) GeoKeyDirectoryTag: GTModelTypeGeoKey = 1 ( ModelTypeProjected) GTRasterTypeGeoKey = 1 (RasterPixelIsArea) ProjectedCSTypeGeoKey = 27700 (PCS_British_National_Grid) PCSCitationGeoKey = "British National Grid, Zone NZ" Remark: the matrix has 100.0 in the off-diagonals due to the 90 degree rotation; increasing I points north, and increasing J points east. +----------------------------------+ 3.2.3. Digital Elevation Model The DMA stores digital elevation models using an equirectangular projection, so that it may be indexed with WGS84 geographic coordinates. Since elevation postings are point-values, the pixels should not be considered as filling areas, but as point-values at grid vertices. To accommodate the base elevation of the Angeles Crest forest, the pixel value of 0 corresponds to an elevation of 1000 meters relative to WGS84 reference ellipsoid. The upper left corner is at 120 degrees West, 32 degrees North, and has a pixel scale of 0.2 degrees/pixel longitude, 0.1 degrees/pixel latitude. ModelTiepointTag=(0.0, 0.0, 0.0, -120.0, 32.0, 1000.0) ModelPixelScale = (0.2, 0.1, 1.0) GeoKeyDirectoryTag: GTModelTypeGeoKey = 2 (ModelTypeGeographic) GTRasterTypeGeoKey = 2 (RasterPixelIsPoint) GeographicTypeGeoKey = 4326 (GCS_WGS_84) VerticalCSTypeGeoKey = 5030 (VertCS_WGS_84_ellipsoid) VerticalCitationGeoKey = "WGS 84 Ellipsoid" VerticalUnitsGeoKey = 1 (Linear_Meter) Remarks: 1) Note the "RasterPixelIsPoint" raster space, indicating that the DEM posting of the first pixel is at the raster point (0,0,0), and therefore corresponds to 120W,32N exactly. 2) The third value of the "PixelScale" is 1.0 to indicate that a single pixel-value unit corresponds to 1 meter, and the last tiepoint value indicates that base value zero indicates 1000m above the reference surface. +----------------------------------+ 4 Extended GeoTIFF +--------------------------------------------------------------------+ This section is for future development TBD. Possible additional GeoKeys for Revision 2.0: PerspectHeightGeoKey (General Vertical Nearsided Perspective) SOMInclinAngleGeoKey (SOM) SOMAscendLongGeoKey (SOM) SOMRevPeriodGeoKey (SOM) SOMEndOfPathGeoKey (SOM) ? is this needed ? SHORT SOMRatioGeoKey (SOM) SOMPathNumGeoKey (SOM) SHORT SOMSatelliteNumGeoKey (SOM) SHORT OEAShapeMGeoKey (Oblated Equal Area) OEAShapeNGeoKey (Oblated Equal Area) OEARotationAngleGeoKey (Oblated Equal Area) Other items for consideration: o Digital Elevation Model information, such as Vertical Datums, Sounding Datums. o Accuracy Keys for linear, circular, and spherical errors, etc. o Source information, such as details of an original coordinate system and of transformations between it and the coordinate system in which data is being exchanged. +--------------------------------------------------------------------+ 5 References +--------------------------------------------------------------------+ 1. EPSG/POSC Projection Coding System Tables. Available via FTP to: ftp://ftpmcmc.cr.usgs.gov/release/geotiff/tables or: ftp://mtritter.jpl.nasa.gov/pub/geotiff/tables 2. TIFF Revision 6.0 Specification: A PDF formatted version is available via FTP to: ftp://ftp.adobe.com/pub/adobe/DeveloperSupport/TechNotes/PDFfiles/TIFF6.pdf PostScript formatted text versiona available at:. ftp://sgi.com/graphics/tiff/TIFF6.ps.Z (compressed) ftp://sgi.com/graphics/tiff/TIFF6.ps (uncompressed) 3. LIBTIFF -- Public Domain TIFF library, available via anonymous FTP to: ftp://sgi.com/graphics/tiff/ 4. Spatial Data Transfer Standard (SDTS) of the USGS. (Federal Information Processing Standard (FIPS) 173): ftp://sdts.er.usgs.gov/pub/sdts/ SDTS Task Force U.S. Geological Survey 526 National Center Reston, VA 22092 E-mail: sdts@usgs.gov 5. Map use: reading, analysis, interpretation. Muehrcke, Phillip C. 1986. Madison, WI: JP Publications. 6. Map projections: a working manual. Snyder, John P. 1987. USGS Professional Paper 1395. Washington, DC: United States Government Printing Office. 7. Notes for GIS and The Geographer's Craft at U. Texas, on the World Wide Web (WWW) (current as of 10 April 1995): http://wwwhost.cc.utexas.edu/ftp/pub/grg/gcraft/notes/notes.html 8. Digital Geographic Information Exchange Standard (DIGEST). Allied Geographic Publication No 3, Edition 1.2 (AGeoP-3) (NATO Unclassified). +--------------------------------------------------------------------+ 6. Appendices +--------------------------------------------------------------------+ +----------------------------------+ 6.1 Tag ID Summary Here are all of the TIFF tags (and their owners) that are used to store GeoTIFF information of any type. It is very unlikely that any other tags will be necessary in the future (since most additional information will be encoded as a GeoKey). ModelPixelScaleTag = 33550 (SoftDesk) ModelTransformationTag = 33920 (Intergraph) ModelTiepointTag = 33922 (Intergraph) GeoKeyDirectoryTag = 34735 (SPOT) GeoDoubleParamsTag = 34736 (SPOT) GeoAsciiParamsTag = 34737 (SPOT) +----------------------------------+ 6.2 Key ID Summary +----------------------------------+ +----------------------------------+ 6.2.1 GeoTIFF Configuration Keys GTModelTypeGeoKey = 1024 /* Section 6.3.1.1 Codes */ GTRasterTypeGeoKey = 1025 /* Section 6.3.1.2 Codes */ GTCitationGeoKey = 1026 /* documentation */ +----------------------------------+ 6.2.2 Geographic CS Parameter Keys GeographicTypeGeoKey = 2048 /* Section 6.3.2.1 Codes */ GeogCitationGeoKey = 2049 /* documentation */ GeogGeodeticDatumGeoKey = 2050 /* Section 6.3.2.2 Codes */ GeogPrimeMeridianGeoKey = 2051 /* Section 6.3.2.4 codes */ GeogLinearUnitsGeoKey = 2052 /* Section 6.3.1.3 Codes */ GeogLinearUnitSizeGeoKey = 2053 /* meters */ GeogAngularUnitsGeoKey = 2054 /* Section 6.3.1.4 Codes */ GeogAngularUnitSizeGeoKey = 2055 /* radians */ GeogEllipsoidGeoKey = 2056 /* Section 6.3.2.3 Codes */ GeogSemiMajorAxisGeoKey = 2057 /* GeogLinearUnits */ GeogSemiMinorAxisGeoKey = 2058 /* GeogLinearUnits */ GeogInvFlatteningGeoKey = 2059 /* ratio */ GeogAzimuthUnitsGeoKey = 2060 /* Section 6.3.1.4 Codes */ GeogPrimeMeridianLongGeoKey = 2061 /* GeogAngularUnit */ +----------------------------------+ 6.2.3 Projected CS Parameter Keys ProjectedCSTypeGeoKey = 3072 /* Section 6.3.3.1 codes */ PCSCitationGeoKey = 3073 /* documentation */ ProjectionGeoKey = 3074 /* Section 6.3.3.2 codes */ ProjCoordTransGeoKey = 3075 /* Section 6.3.3.3 codes */ ProjLinearUnitsGeoKey = 3076 /* Section 6.3.1.3 codes */ ProjLinearUnitSizeGeoKey = 3077 /* meters */ ProjStdParallelGeoKey = 3078 /* GeogAngularUnit */ ProjStdParallel2GeoKey = 3079 /* GeogAngularUnit */ ProjOriginLongGeoKey = 3080 /* GeogAngularUnit */ ProjOriginLatGeoKey = 3081 /* GeogAngularUnit */ ProjFalseEastingGeoKey = 3082 /* ProjLinearUnits */ ProjFalseNorthingGeoKey = 3083 /* ProjLinearUnits */ ProjFalseOriginLongGeoKey = 3084 /* GeogAngularUnit */ ProjFalseOriginLatGeoKey = 3085 /* GeogAngularUnit */ ProjFalseOriginEastingGeoKey = 3086 /* ProjLinearUnits */ ProjFalseOriginNorthingGeoKey = 3087 /* ProjLinearUnits */ ProjCenterLongGeoKey = 3088 /* GeogAngularUnit */ ProjCenterLatGeoKey = 3089 /* GeogAngularUnit */ ProjCenterEastingGeoKey = 3090 /* ProjLinearUnits */ ProjCenterNorthingGeoKey = 3091 /* ProjLinearUnits */ ProjScaleAtOriginGeoKey = 3092 /* ratio */ ProjScaleAtCenterGeoKey = 3093 /* ratio */ ProjAzimuthAngleGeoKey = 3094 /* GeogAzimuthUnit */ ProjStraightVertPoleLongGeoKey = 3095 /* GeogAngularUnit */ +----------------------------------+ 6.2.4 Vertical CS Keys VerticalCSTypeGeoKey = 4096 /* Section 6.3.4.1 codes */ VerticalCitationGeoKey = 4097 /* documentation */ VerticalDatumGeoKey = 4098 /* Section 6.3.4.2 codes */ VerticalUnitsGeoKey = 4099 /* Section 6.3.1.3 codes */ +---------------------------------------------------------------------+ +----------------------------------+ 6.3 Key Code Summary +----------------------------------+ 6.3.1 GeoTIFF General Codes This section includes the general "Configuration" key codes, as well as general codes which are used by more than one key (e.g. units codes). +----------------------------------+ 6.3.1.1 Model Type Codes Ranges: 0 = undefined [ 1, 32766] = GeoTIFF Reserved Codes 32767 = user-defined [32768, 65535] = Private User Implementations GeoTIFF defined CS Model Type Codes: ModelTypeProjected = 1 /* Projection Coordinate System */ ModelTypeGeographic = 2 /* Geographic latitude-longitude System */ ModelTypeGeocentric = 3 /* Geocentric (X,Y,Z) Coordinate System */ Notes: 1. ModelTypeGeographic and ModelTypeProjected correspond to the FGDC metadata Geographic and Planar-Projected coordinate system types. +----------------------------------+ 6.3.1.2 Raster Type Codes Ranges: 0 = undefined [ 1, 1023] = Raster Type Codes (GeoTIFF Defined) [1024, 32766] = Reserved 32767 = user-defined [32768, 65535]= Private User Implementations Values: RasterPixelIsArea = 1 RasterPixelIsPoint = 2 Note: Use of "user-defined" or "undefined" raster codes is not recommended. +----------------------------------+ 6.3.1.3 Linear Units Codes There are several different kinds of units that may be used in geographically related raster data: linear units, angular units, units of time (e.g. for radar-return), CCD-voltages, etc. For this reason there will be a single, unique range for each kind of unit, broken down into the following currently defined ranges: Ranges: 0 = undefined [ 1, 2000] = Obsolete GeoTIFF codes [2001, 8999] = Reserved by GeoTIFF [9000, 9099] = EPSG Linear Units. [9100, 9199] = EPSG Angular Units. 32767 = user-defined unit [32768, 65535]= Private User Implementations Linear Unit Values (See the ESPG/POSC tables for definition): Linear_Meter = 9001 Linear_Foot = 9002 Linear_Foot_US_Survey = 9003 Linear_Foot_Modified_American = 9004 Linear_Foot_Clarke = 9005 Linear_Foot_Indian = 9006 Linear_Link = 9007 Linear_Link_Benoit = 9008 Linear_Link_Sears = 9009 Linear_Chain_Benoit = 9010 Linear_Chain_Sears = 9011 Linear_Yard_Sears = 9012 Linear_Yard_Indian = 9013 Linear_Fathom = 9014 Linear_Mile_International_Nautical = 9015 +----------------------------------+ 6.3.1.4 Angular Units Codes These codes shall be used for any key that requires specification of an angular unit of measurement. Angular Units Angular_Radian = 9101 Angular_Degree = 9102 Angular_Arc_Minute = 9103 Angular_Arc_Second = 9104 Angular_Grad = 9105 Angular_Gon = 9106 Angular_DMS = 9107 Angular_DMS_Hemisphere = 9108 +----------------------------------+ 6.3.2 Geographic CS Codes +----------------------------------+ 6.3.2.1 Geographic CS Type Codes Note: A Geographic coordinate system consists of both a datum and a Prime Meridian. Some of the names are very similar, and differ only in the Prime Meridian, so be sure to use the correct one. The codes beginning with GCSE_xxx are unspecified GCS which use ellipsoid (xxx); it is recommended that only the codes beginning with GCS_ be used if possible. Ranges: 0 = undefined [ 1, 1000] = Obsolete EPSG/POSC Geographic Codes [ 1001, 3999] = Reserved by GeoTIFF [ 4000, 4199] = EPSG GCS Based on Ellipsoid only [ 4200, 4999] = EPSG GCS Based on EPSG Datum [ 5000, 32766] = Reserved by GeoTIFF 32767 = user-defined GCS [32768, 65535] = Private User Implementations Values: Note: Geodetic datum using Greenwich PM have codes equal to the corresponding Datum code - 2000. GCS_Adindan = 4201 GCS_AGD66 = 4202 GCS_AGD84 = 4203 GCS_Ain_el_Abd = 4204 GCS_Afgooye = 4205 GCS_Agadez = 4206 GCS_Lisbon = 4207 GCS_Aratu = 4208 GCS_Arc_1950 = 4209 GCS_Arc_1960 = 4210 GCS_Batavia = 4211 GCS_Barbados = 4212 GCS_Beduaram = 4213 GCS_Beijing_1954 = 4214 GCS_Belge_1950 = 4215 GCS_Bermuda_1957 = 4216 GCS_Bern_1898 = 4217 GCS_Bogota = 4218 GCS_Bukit_Rimpah = 4219 GCS_Camacupa = 4220 GCS_Campo_Inchauspe = 4221 GCS_Cape = 4222 GCS_Carthage = 4223 GCS_Chua = 4224 GCS_Corrego_Alegre = 4225 GCS_Cote_d_Ivoire = 4226 GCS_Deir_ez_Zor = 4227 GCS_Douala = 4228 GCS_Egypt_1907 = 4229 GCS_ED50 = 4230 GCS_ED87 = 4231 GCS_Fahud = 4232 GCS_Gandajika_1970 = 4233 GCS_Garoua = 4234 GCS_Guyane_Francaise = 4235 GCS_Hu_Tzu_Shan = 4236 GCS_HD72 = 4237 GCS_ID74 = 4238 GCS_Indian_1954 = 4239 GCS_Indian_1975 = 4240 GCS_Jamaica_1875 = 4241 GCS_JAD69 = 4242 GCS_Kalianpur = 4243 GCS_Kandawala = 4244 GCS_Kertau = 4245 GCS_KOC = 4246 GCS_La_Canoa = 4247 GCS_PSAD56 = 4248 GCS_Lake = 4249 GCS_Leigon = 4250 GCS_Liberia_1964 = 4251 GCS_Lome = 4252 GCS_Luzon_1911 = 4253 GCS_Hito_XVIII_1963 = 4254 GCS_Herat_North = 4255 GCS_Mahe_1971 = 4256 GCS_Makassar = 4257 GCS_EUREF89 = 4258 GCS_Malongo_1987 = 4259 GCS_Manoca = 4260 GCS_Merchich = 4261 GCS_Massawa = 4262 GCS_Minna = 4263 GCS_Mhast = 4264 GCS_Monte_Mario = 4265 GCS_M_poraloko = 4266 GCS_NAD27 = 4267 GCS_NAD_Michigan = 4268 GCS_NAD83 = 4269 GCS_Nahrwan_1967 = 4270 GCS_Naparima_1972 = 4271 GCS_GD49 = 4272 GCS_NGO_1948 = 4273 GCS_Datum_73 = 4274 GCS_NTF = 4275 GCS_NSWC_9Z_2 = 4276 GCS_OSGB_1936 = 4277 GCS_OSGB70 = 4278 GCS_OS_SN80 = 4279 GCS_Padang = 4280 GCS_Palestine_1923 = 4281 GCS_Pointe_Noire = 4282 GCS_GDA94 = 4283 GCS_Pulkovo_1942 = 4284 GCS_Qatar = 4285 GCS_Qatar_1948 = 4286 GCS_Qornoq = 4287 GCS_Loma_Quintana = 4288 GCS_Amersfoort = 4289 GCS_RT38 = 4290 GCS_SAD69 = 4291 GCS_Sapper_Hill_1943 = 4292 GCS_Schwarzeck = 4293 GCS_Segora = 4294 GCS_Serindung = 4295 GCS_Sudan = 4296 GCS_Tananarive = 4297 GCS_Timbalai_1948 = 4298 GCS_TM65 = 4299 GCS_TM75 = 4300 GCS_Tokyo = 4301 GCS_Trinidad_1903 = 4302 GCS_TC_1948 = 4303 GCS_Voirol_1875 = 4304 GCS_Voirol_Unifie = 4305 GCS_Bern_1938 = 4306 GCS_Nord_Sahara_1959 = 4307 GCS_Stockholm_1938 = 4308 GCS_Yacare = 4309 GCS_Yoff = 4310 GCS_Zanderij = 4311 GCS_MGI = 4312 GCS_Belge_1972 = 4313 GCS_DHDN = 4314 GCS_Conakry_1905 = 4315 GCS_WGS_72 = 4322 GCS_WGS_72BE = 4324 GCS_WGS_84 = 4326 GCS_Bern_1898_Bern = 4801 GCS_Bogota_Bogota = 4802 GCS_Lisbon_Lisbon = 4803 GCS_Makassar_Jakarta = 4804 GCS_MGI_Ferro = 4805 GCS_Monte_Mario_Rome = 4806 GCS_NTF_Paris = 4807 GCS_Padang_Jakarta = 4808 GCS_Belge_1950_Brussels = 4809 GCS_Tananarive_Paris = 4810 GCS_Voirol_1875_Paris = 4811 GCS_Voirol_Unifie_Paris = 4812 GCS_Batavia_Jakarta = 4813 GCS_ATF_Paris = 4901 GCS_NDG_Paris = 4902 Ellipsoid-Only GCS: Note: the numeric code is equal to the code of the correspoding EPSG ellipsoid, minus 3000. GCSE_Airy1830 = 4001 GCSE_AiryModified1849 = 4002 GCSE_AustralianNationalSpheroid = 4003 GCSE_Bessel1841 = 4004 GCSE_BesselModified = 4005 GCSE_BesselNamibia = 4006 GCSE_Clarke1858 = 4007 GCSE_Clarke1866 = 4008 GCSE_Clarke1866Michigan = 4009 GCSE_Clarke1880_Benoit = 4010 GCSE_Clarke1880_IGN = 4011 GCSE_Clarke1880_RGS = 4012 GCSE_Clarke1880_Arc = 4013 GCSE_Clarke1880_SGA1922 = 4014 GCSE_Everest1830_1937Adjustment = 4015 GCSE_Everest1830_1967Definition = 4016 GCSE_Everest1830_1975Definition = 4017 GCSE_Everest1830Modified = 4018 GCSE_GRS1980 = 4019 GCSE_Helmert1906 = 4020 GCSE_IndonesianNationalSpheroid = 4021 GCSE_International1924 = 4022 GCSE_International1967 = 4023 GCSE_Krassowsky1940 = 4024 GCSE_NWL9D = 4025 GCSE_NWL10D = 4026 GCSE_Plessis1817 = 4027 GCSE_Struve1860 = 4028 GCSE_WarOffice = 4029 GCSE_WGS84 = 4030 GCSE_GEM10C = 4031 GCSE_OSU86F = 4032 GCSE_OSU91A = 4033 GCSE_Clarke1880 = 4034 GCSE_Sphere = 4035 +----------------------------------+ 6.3.2.2 Geodetic Datum Codes Note: these codes do not include the Prime Meridian; if possible use the GCS codes above if the datum and Prime Meridian are on the list. Also, as with the GCS codes, the codes beginning with DatumE_xxx refer only to the specified ellipsoid (xxx); if possible use instead the named datums beginning with Datum_xxx Ranges: 0 = undefined [ 1, 1000] = Obsolete EPSG/POSC Datum Codes [ 1001, 5999] = Reserved by GeoTIFF [ 6000, 6199] = EPSG Datum Based on Ellipsoid only [ 6200, 6999] = EPSG Datum Based on EPSG Datum [ 6322, 6327] = WGS Datum [ 6900, 6999] = Archaic Datum [ 7000, 32766] = Reserved by GeoTIFF 32767 = user-defined GCS [32768, 65535] = Private User Implementations Values: Datum_Adindan = 6201 Datum_Australian_Geodetic_Datum_1966 = 6202 Datum_Australian_Geodetic_Datum_1984 = 6203 Datum_Ain_el_Abd_1970 = 6204 Datum_Afgooye = 6205 Datum_Agadez = 6206 Datum_Lisbon = 6207 Datum_Aratu = 6208 Datum_Arc_1950 = 6209 Datum_Arc_1960 = 6210 Datum_Batavia = 6211 Datum_Barbados = 6212 Datum_Beduaram = 6213 Datum_Beijing_1954 = 6214 Datum_Reseau_National_Belge_1950 = 6215 Datum_Bermuda_1957 = 6216 Datum_Bern_1898 = 6217 Datum_Bogota = 6218 Datum_Bukit_Rimpah = 6219 Datum_Camacupa = 6220 Datum_Campo_Inchauspe = 6221 Datum_Cape = 6222 Datum_Carthage = 6223 Datum_Chua = 6224 Datum_Corrego_Alegre = 6225 Datum_Cote_d_Ivoire = 6226 Datum_Deir_ez_Zor = 6227 Datum_Douala = 6228 Datum_Egypt_1907 = 6229 Datum_European_Datum_1950 = 6230 Datum_European_Datum_1987 = 6231 Datum_Fahud = 6232 Datum_Gandajika_1970 = 6233 Datum_Garoua = 6234 Datum_Guyane_Francaise = 6235 Datum_Hu_Tzu_Shan = 6236 Datum_Hungarian_Datum_1972 = 6237 Datum_Indonesian_Datum_1974 = 6238 Datum_Indian_1954 = 6239 Datum_Indian_1975 = 6240 Datum_Jamaica_1875 = 6241 Datum_Jamaica_1969 = 6242 Datum_Kalianpur = 6243 Datum_Kandawala = 6244 Datum_Kertau = 6245 Datum_Kuwait_Oil_Company = 6246 Datum_La_Canoa = 6247 Datum_Provisional_S_American_Datum_1956 = 6248 Datum_Lake = 6249 Datum_Leigon = 6250 Datum_Liberia_1964 = 6251 Datum_Lome = 6252 Datum_Luzon_1911 = 6253 Datum_Hito_XVIII_1963 = 6254 Datum_Herat_North = 6255 Datum_Mahe_1971 = 6256 Datum_Makassar = 6257 Datum_European_Reference_System_1989 = 6258 Datum_Malongo_1987 = 6259 Datum_Manoca = 6260 Datum_Merchich = 6261 Datum_Massawa = 6262 Datum_Minna = 6263 Datum_Mhast = 6264 Datum_Monte_Mario = 6265 Datum_M_poraloko = 6266 Datum_North_American_Datum_1927 = 6267 Datum_NAD_Michigan = 6268 Datum_North_American_Datum_1983 = 6269 Datum_Nahrwan_1967 = 6270 Datum_Naparima_1972 = 6271 Datum_New_Zealand_Geodetic_Datum_1949 = 6272 Datum_NGO_1948 = 6273 Datum_Datum_73 = 6274 Datum_Nouvelle_Triangulation_Francaise = 6275 Datum_NSWC_9Z_2 = 6276 Datum_OSGB_1936 = 6277 Datum_OSGB_1970_SN = 6278 Datum_OS_SN_1980 = 6279 Datum_Padang_1884 = 6280 Datum_Palestine_1923 = 6281 Datum_Pointe_Noire = 6282 Datum_Geocentric_Datum_of_Australia_1994 = 6283 Datum_Pulkovo_1942 = 6284 Datum_Qatar = 6285 Datum_Qatar_1948 = 6286 Datum_Qornoq = 6287 Datum_Loma_Quintana = 6288 Datum_Amersfoort = 6289 Datum_RT38 = 6290 Datum_South_American_Datum_1969 = 6291 Datum_Sapper_Hill_1943 = 6292 Datum_Schwarzeck = 6293 Datum_Segora = 6294 Datum_Serindung = 6295 Datum_Sudan = 6296 Datum_Tananarive_1925 = 6297 Datum_Timbalai_1948 = 6298 Datum_TM65 = 6299 Datum_TM75 = 6300 Datum_Tokyo = 6301 Datum_Trinidad_1903 = 6302 Datum_Trucial_Coast_1948 = 6303 Datum_Voirol_1875 = 6304 Datum_Voirol_Unifie_1960 = 6305 Datum_Bern_1938 = 6306 Datum_Nord_Sahara_1959 = 6307 Datum_Stockholm_1938 = 6308 Datum_Yacare = 6309 Datum_Yoff = 6310 Datum_Zanderij = 6311 Datum_Militar_Geographische_Institut = 6312 Datum_Reseau_National_Belge_1972 = 6313 Datum_Deutsche_Hauptdreiecksnetz = 6314 Datum_Conakry_1905 = 6315 Datum_WGS72 = 6322 Datum_WGS72_Transit_Broadcast_Ephemeris = 6324 Datum_WGS84 = 6326 Datum_Ancienne_Triangulation_Francaise = 6901 Datum_Nord_de_Guerre = 6902 Ellipsoid-Only Datum: Note: the numeric code is equal to the corresponding ellipsoid code, minus 1000. DatumE_Airy1830 = 6001 DatumE_AiryModified1849 = 6002 DatumE_AustralianNationalSpheroid = 6003 DatumE_Bessel1841 = 6004 DatumE_BesselModified = 6005 DatumE_BesselNamibia = 6006 DatumE_Clarke1858 = 6007 DatumE_Clarke1866 = 6008 DatumE_Clarke1866Michigan = 6009 DatumE_Clarke1880_Benoit = 6010 DatumE_Clarke1880_IGN = 6011 DatumE_Clarke1880_RGS = 6012 DatumE_Clarke1880_Arc = 6013 DatumE_Clarke1880_SGA1922 = 6014 DatumE_Everest1830_1937Adjustment = 6015 DatumE_Everest1830_1967Definition = 6016 DatumE_Everest1830_1975Definition = 6017 DatumE_Everest1830Modified = 6018 DatumE_GRS1980 = 6019 DatumE_Helmert1906 = 6020 DatumE_IndonesianNationalSpheroid = 6021 DatumE_International1924 = 6022 DatumE_International1967 = 6023 DatumE_Krassowsky1960 = 6024 DatumE_NWL9D = 6025 DatumE_NWL10D = 6026 DatumE_Plessis1817 = 6027 DatumE_Struve1860 = 6028 DatumE_WarOffice = 6029 DatumE_WGS84 = 6030 DatumE_GEM10C = 6031 DatumE_OSU86F = 6032 DatumE_OSU91A = 6033 DatumE_Clarke1880 = 6034 DatumE_Sphere = 6035 +----------------------------------+ 6.3.2.3 Ellipsoid Codes Ranges: 0 = undefined [ 1, 1000] = Obsolete EPSG/POSC Ellipsoid codes [1001, 6999] = Reserved by GeoTIFF [7000, 7999] = EPSG Ellipsoid codes [8000, 32766] = Reserved by GeoTIFF 32767 = user-defined [32768, 65535] = Private User Implementations Values: Ellipse_Airy_1830 = 7001 Ellipse_Airy_Modified_1849 = 7002 Ellipse_Australian_National_Spheroid = 7003 Ellipse_Bessel_1841 = 7004 Ellipse_Bessel_Modified = 7005 Ellipse_Bessel_Namibia = 7006 Ellipse_Clarke_1858 = 7007 Ellipse_Clarke_1866 = 7008 Ellipse_Clarke_1866_Michigan = 7009 Ellipse_Clarke_1880_Benoit = 7010 Ellipse_Clarke_1880_IGN = 7011 Ellipse_Clarke_1880_RGS = 7012 Ellipse_Clarke_1880_Arc = 7013 Ellipse_Clarke_1880_SGA_1922 = 7014 Ellipse_Everest_1830_1937_Adjustment = 7015 Ellipse_Everest_1830_1967_Definition = 7016 Ellipse_Everest_1830_1975_Definition = 7017 Ellipse_Everest_1830_Modified = 7018 Ellipse_GRS_1980 = 7019 Ellipse_Helmert_1906 = 7020 Ellipse_Indonesian_National_Spheroid = 7021 Ellipse_International_1924 = 7022 Ellipse_International_1967 = 7023 Ellipse_Krassowsky_1940 = 7024 Ellipse_NWL_9D = 7025 Ellipse_NWL_10D = 7026 Ellipse_Plessis_1817 = 7027 Ellipse_Struve_1860 = 7028 Ellipse_War_Office = 7029 Ellipse_WGS_84 = 7030 Ellipse_GEM_10C = 7031 Ellipse_OSU86F = 7032 Ellipse_OSU91A = 7033 Ellipse_Clarke_1880 = 7034 Ellipse_Sphere = 7035 +----------------------------------+ 6.3.2.4 Prime Meridian Codes Ranges: 0 = undefined [ 1, 100] = Obsolete EPSG/POSC Prime Meridian codes [ 101, 7999] = Reserved by GeoTIFF [ 8000, 8999] = EPSG Prime Meridian Codes [ 9000, 32766] = Reserved by GeoTIFF 32767 = user-defined [32768, 65535] = Private User Implementations Values: PM_Greenwich = 8901 PM_Lisbon = 8902 PM_Paris = 8903 PM_Bogota = 8904 PM_Madrid = 8905 PM_Rome = 8906 PM_Bern = 8907 PM_Jakarta = 8908 PM_Ferro = 8909 PM_Brussels = 8910 PM_Stockholm = 8911 +----------------------------------+ 6.3.3 Projected CS Codes +----------------------------------+ 6.3.3.1 Projected CS Type Codes Ranges: [ 1, 1000] = Obsolete EPSG/POSC Projection System Codes [20000, 32760] = EPSG Projection System codes 32767 = user-defined [32768, 65535] = Private User Implementations Special Ranges: 1. For PCS utilising GeogCS with code in range 4201 through 4321 (i.e. geodetic datum code 6201 through 6319): As far as is possible the PCS code will be of theformat gggzz where ggg is (geodetic datum code -2000) and zz is zone. 2. For PCS utilising GeogCS with code out of range 4201 through 4321 (i.e.geodetic datum code 6201 through 6319). PCS code 20xxx where xxx is a sequential number. 3. Other: WGS72 / UTM northern hemisphere: 322zz where zz is UTM zone number WGS72 / UTM southern hemisphere: 323zz where zz is UTM zone number WGS72BE / UTM northern hemisphere: 324zz where zz is UTM zone number WGS72BE / UTM southern hemisphere: 325zz where zz is UTM zone number WGS84 / UTM northern hemisphere: 326zz where zz is UTM zone number WGS84 / UTM southern hemisphere: 327zz where zz is UTM zone number US State Plane (NAD27): 267xx/320xx US State Plane (NAD83): 269xx/321xx Values: PCS_Adindan_UTM_zone_37N = 20137 PCS_Adindan_UTM_zone_38N = 20138 PCS_AGD66_AMG_zone_48 = 20248 PCS_AGD66_AMG_zone_49 = 20249 PCS_AGD66_AMG_zone_50 = 20250 PCS_AGD66_AMG_zone_51 = 20251 PCS_AGD66_AMG_zone_52 = 20252 PCS_AGD66_AMG_zone_53 = 20253 PCS_AGD66_AMG_zone_54 = 20254 PCS_AGD66_AMG_zone_55 = 20255 PCS_AGD66_AMG_zone_56 = 20256 PCS_AGD66_AMG_zone_57 = 20257 PCS_AGD66_AMG_zone_58 = 20258 PCS_AGD84_AMG_zone_48 = 20348 PCS_AGD84_AMG_zone_49 = 20349 PCS_AGD84_AMG_zone_50 = 20350 PCS_AGD84_AMG_zone_51 = 20351 PCS_AGD84_AMG_zone_52 = 20352 PCS_AGD84_AMG_zone_53 = 20353 PCS_AGD84_AMG_zone_54 = 20354 PCS_AGD84_AMG_zone_55 = 20355 PCS_AGD84_AMG_zone_56 = 20356 PCS_AGD84_AMG_zone_57 = 20357 PCS_AGD84_AMG_zone_58 = 20358 PCS_Ain_el_Abd_UTM_zone_37N = 20437 PCS_Ain_el_Abd_UTM_zone_38N = 20438 PCS_Ain_el_Abd_UTM_zone_39N = 20439 PCS_Ain_el_Abd_Bahrain_Grid = 20499 PCS_Afgooye_UTM_zone_38N = 20538 PCS_Afgooye_UTM_zone_39N = 20539 PCS_Lisbon_Portugese_Grid = 20700 PCS_Aratu_UTM_zone_22S = 20822 PCS_Aratu_UTM_zone_23S = 20823 PCS_Aratu_UTM_zone_24S = 20824 PCS_Arc_1950_Lo13 = 20973 PCS_Arc_1950_Lo15 = 20975 PCS_Arc_1950_Lo17 = 20977 PCS_Arc_1950_Lo19 = 20979 PCS_Arc_1950_Lo21 = 20981 PCS_Arc_1950_Lo23 = 20983 PCS_Arc_1950_Lo25 = 20985 PCS_Arc_1950_Lo27 = 20987 PCS_Arc_1950_Lo29 = 20989 PCS_Arc_1950_Lo31 = 20991 PCS_Arc_1950_Lo33 = 20993 PCS_Arc_1950_Lo35 = 20995 PCS_Batavia_NEIEZ = 21100 PCS_Batavia_UTM_zone_48S = 21148 PCS_Batavia_UTM_zone_49S = 21149 PCS_Batavia_UTM_zone_50S = 21150 PCS_Beijing_Gauss_zone_13 = 21413 PCS_Beijing_Gauss_zone_14 = 21414 PCS_Beijing_Gauss_zone_15 = 21415 PCS_Beijing_Gauss_zone_16 = 21416 PCS_Beijing_Gauss_zone_17 = 21417 PCS_Beijing_Gauss_zone_18 = 21418 PCS_Beijing_Gauss_zone_19 = 21419 PCS_Beijing_Gauss_zone_20 = 21420 PCS_Beijing_Gauss_zone_21 = 21421 PCS_Beijing_Gauss_zone_22 = 21422 PCS_Beijing_Gauss_zone_23 = 21423 PCS_Beijing_Gauss_13N = 21473 PCS_Beijing_Gauss_14N = 21474 PCS_Beijing_Gauss_15N = 21475 PCS_Beijing_Gauss_16N = 21476 PCS_Beijing_Gauss_17N = 21477 PCS_Beijing_Gauss_18N = 21478 PCS_Beijing_Gauss_19N = 21479 PCS_Beijing_Gauss_20N = 21480 PCS_Beijing_Gauss_21N = 21481 PCS_Beijing_Gauss_22N = 21482 PCS_Beijing_Gauss_23N = 21483 PCS_Belge_Lambert_50 = 21500 PCS_Bern_1898_Swiss_Old = 21790 PCS_Bogota_UTM_zone_17N = 21817 PCS_Bogota_UTM_zone_18N = 21818 PCS_Bogota_Colombia_3W = 21891 PCS_Bogota_Colombia_Bogota = 21892 PCS_Bogota_Colombia_3E = 21893 PCS_Bogota_Colombia_6E = 21894 PCS_Camacupa_UTM_32S = 22032 PCS_Camacupa_UTM_33S = 22033 PCS_C_Inchauspe_Argentina_1 = 22191 PCS_C_Inchauspe_Argentina_2 = 22192 PCS_C_Inchauspe_Argentina_3 = 22193 PCS_C_Inchauspe_Argentina_4 = 22194 PCS_C_Inchauspe_Argentina_5 = 22195 PCS_C_Inchauspe_Argentina_6 = 22196 PCS_C_Inchauspe_Argentina_7 = 22197 PCS_Carthage_UTM_zone_32N = 22332 PCS_Carthage_Nord_Tunisie = 22391 PCS_Carthage_Sud_Tunisie = 22392 PCS_Corrego_Alegre_UTM_23S = 22523 PCS_Corrego_Alegre_UTM_24S = 22524 PCS_Douala_UTM_zone_32N = 22832 PCS_Egypt_1907_Red_Belt = 22992 PCS_Egypt_1907_Purple_Belt = 22993 PCS_Egypt_1907_Ext_Purple = 22994 PCS_ED50_UTM_zone_28N = 23028 PCS_ED50_UTM_zone_29N = 23029 PCS_ED50_UTM_zone_30N = 23030 PCS_ED50_UTM_zone_31N = 23031 PCS_ED50_UTM_zone_32N = 23032 PCS_ED50_UTM_zone_33N = 23033 PCS_ED50_UTM_zone_34N = 23034 PCS_ED50_UTM_zone_35N = 23035 PCS_ED50_UTM_zone_36N = 23036 PCS_ED50_UTM_zone_37N = 23037 PCS_ED50_UTM_zone_38N = 23038 PCS_Fahud_UTM_zone_39N = 23239 PCS_Fahud_UTM_zone_40N = 23240 PCS_Garoua_UTM_zone_33N = 23433 PCS_ID74_UTM_zone_46N = 23846 PCS_ID74_UTM_zone_47N = 23847 PCS_ID74_UTM_zone_48N = 23848 PCS_ID74_UTM_zone_49N = 23849 PCS_ID74_UTM_zone_50N = 23850 PCS_ID74_UTM_zone_51N = 23851 PCS_ID74_UTM_zone_52N = 23852 PCS_ID74_UTM_zone_53N = 23853 PCS_ID74_UTM_zone_46S = 23886 PCS_ID74_UTM_zone_47S = 23887 PCS_ID74_UTM_zone_48S = 23888 PCS_ID74_UTM_zone_49S = 23889 PCS_ID74_UTM_zone_50S = 23890 PCS_ID74_UTM_zone_51S = 23891 PCS_ID74_UTM_zone_52S = 23892 PCS_ID74_UTM_zone_53S = 23893 PCS_ID74_UTM_zone_54S = 23894 PCS_Indian_1954_UTM_47N = 23947 PCS_Indian_1954_UTM_48N = 23948 PCS_Indian_1975_UTM_47N = 24047 PCS_Indian_1975_UTM_48N = 24048 PCS_Jamaica_1875_Old_Grid = 24100 PCS_JAD69_Jamaica_Grid = 24200 PCS_Kalianpur_India_0 = 24370 PCS_Kalianpur_India_I = 24371 PCS_Kalianpur_India_IIa = 24372 PCS_Kalianpur_India_IIIa = 24373 PCS_Kalianpur_India_IVa = 24374 PCS_Kalianpur_India_IIb = 24382 PCS_Kalianpur_India_IIIb = 24383 PCS_Kalianpur_India_IVb = 24384 PCS_Kertau_Singapore_Grid = 24500 PCS_Kertau_UTM_zone_47N = 24547 PCS_Kertau_UTM_zone_48N = 24548 PCS_La_Canoa_UTM_zone_20N = 24720 PCS_La_Canoa_UTM_zone_21N = 24721 PCS_PSAD56_UTM_zone_18N = 24818 PCS_PSAD56_UTM_zone_19N = 24819 PCS_PSAD56_UTM_zone_20N = 24820 PCS_PSAD56_UTM_zone_21N = 24821 PCS_PSAD56_UTM_zone_17S = 24877 PCS_PSAD56_UTM_zone_18S = 24878 PCS_PSAD56_UTM_zone_19S = 24879 PCS_PSAD56_UTM_zone_20S = 24880 PCS_PSAD56_Peru_west_zone = 24891 PCS_PSAD56_Peru_central = 24892 PCS_PSAD56_Peru_east_zone = 24893 PCS_Leigon_Ghana_Grid = 25000 PCS_Lome_UTM_zone_31N = 25231 PCS_Luzon_Philippines_I = 25391 PCS_Luzon_Philippines_II = 25392 PCS_Luzon_Philippines_III = 25393 PCS_Luzon_Philippines_IV = 25394 PCS_Luzon_Philippines_V = 25395 PCS_Makassar_NEIEZ = 25700 PCS_Malongo_1987_UTM_32S = 25932 PCS_Merchich_Nord_Maroc = 26191 PCS_Merchich_Sud_Maroc = 26192 PCS_Merchich_Sahara = 26193 PCS_Massawa_UTM_zone_37N = 26237 PCS_Minna_UTM_zone_31N = 26331 PCS_Minna_UTM_zone_32N = 26332 PCS_Minna_Nigeria_West = 26391 PCS_Minna_Nigeria_Mid_Belt = 26392 PCS_Minna_Nigeria_East = 26393 PCS_Mhast_UTM_zone_32S = 26432 PCS_Monte_Mario_Italy_1 = 26591 PCS_Monte_Mario_Italy_2 = 26592 PCS_M_poraloko_UTM_32N = 26632 PCS_M_poraloko_UTM_32S = 26692 PCS_NAD27_UTM_zone_3N = 26703 PCS_NAD27_UTM_zone_4N = 26704 PCS_NAD27_UTM_zone_5N = 26705 PCS_NAD27_UTM_zone_6N = 26706 PCS_NAD27_UTM_zone_7N = 26707 PCS_NAD27_UTM_zone_8N = 26708 PCS_NAD27_UTM_zone_9N = 26709 PCS_NAD27_UTM_zone_10N = 26710 PCS_NAD27_UTM_zone_11N = 26711 PCS_NAD27_UTM_zone_12N = 26712 PCS_NAD27_UTM_zone_13N = 26713 PCS_NAD27_UTM_zone_14N = 26714 PCS_NAD27_UTM_zone_15N = 26715 PCS_NAD27_UTM_zone_16N = 26716 PCS_NAD27_UTM_zone_17N = 26717 PCS_NAD27_UTM_zone_18N = 26718 PCS_NAD27_UTM_zone_19N = 26719 PCS_NAD27_UTM_zone_20N = 26720 PCS_NAD27_UTM_zone_21N = 26721 PCS_NAD27_UTM_zone_22N = 26722 PCS_NAD27_Alabama_East = 26729 PCS_NAD27_Alabama_West = 26730 PCS_NAD27_Alaska_zone_1 = 26731 PCS_NAD27_Alaska_zone_2 = 26732 PCS_NAD27_Alaska_zone_3 = 26733 PCS_NAD27_Alaska_zone_4 = 26734 PCS_NAD27_Alaska_zone_5 = 26735 PCS_NAD27_Alaska_zone_6 = 26736 PCS_NAD27_Alaska_zone_7 = 26737 PCS_NAD27_Alaska_zone_8 = 26738 PCS_NAD27_Alaska_zone_9 = 26739 PCS_NAD27_Alaska_zone_10 = 26740 PCS_NAD27_California_I = 26741 PCS_NAD27_California_II = 26742 PCS_NAD27_California_III = 26743 PCS_NAD27_California_IV = 26744 PCS_NAD27_California_V = 26745 PCS_NAD27_California_VI = 26746 PCS_NAD27_California_VII = 26747 PCS_NAD27_Arizona_East = 26748 PCS_NAD27_Arizona_Central = 26749 PCS_NAD27_Arizona_West = 26750 PCS_NAD27_Arkansas_North = 26751 PCS_NAD27_Arkansas_South = 26752 PCS_NAD27_Colorado_North = 26753 PCS_NAD27_Colorado_Central = 26754 PCS_NAD27_Colorado_South = 26755 PCS_NAD27_Connecticut = 26756 PCS_NAD27_Delaware = 26757 PCS_NAD27_Florida_East = 26758 PCS_NAD27_Florida_West = 26759 PCS_NAD27_Florida_North = 26760 PCS_NAD27_Hawaii_zone_1 = 26761 PCS_NAD27_Hawaii_zone_2 = 26762 PCS_NAD27_Hawaii_zone_3 = 26763 PCS_NAD27_Hawaii_zone_4 = 26764 PCS_NAD27_Hawaii_zone_5 = 26765 PCS_NAD27_Georgia_East = 26766 PCS_NAD27_Georgia_West = 26767 PCS_NAD27_Idaho_East = 26768 PCS_NAD27_Idaho_Central = 26769 PCS_NAD27_Idaho_West = 26770 PCS_NAD27_Illinois_East = 26771 PCS_NAD27_Illinois_West = 26772 PCS_NAD27_Indiana_East = 26773 PCS_NAD27_BLM_14N_feet = 26774 PCS_NAD27_Indiana_West = 26774 PCS_NAD27_BLM_15N_feet = 26775 PCS_NAD27_Iowa_North = 26775 PCS_NAD27_BLM_16N_feet = 26776 PCS_NAD27_Iowa_South = 26776 PCS_NAD27_BLM_17N_feet = 26777 PCS_NAD27_Kansas_North = 26777 PCS_NAD27_Kansas_South = 26778 PCS_NAD27_Kentucky_North = 26779 PCS_NAD27_Kentucky_South = 26780 PCS_NAD27_Louisiana_North = 26781 PCS_NAD27_Louisiana_South = 26782 PCS_NAD27_Maine_East = 26783 PCS_NAD27_Maine_West = 26784 PCS_NAD27_Maryland = 26785 PCS_NAD27_Massachusetts = 26786 PCS_NAD27_Massachusetts_Is = 26787 PCS_NAD27_Michigan_North = 26788 PCS_NAD27_Michigan_Central = 26789 PCS_NAD27_Michigan_South = 26790 PCS_NAD27_Minnesota_North = 26791 PCS_NAD27_Minnesota_Cent = 26792 PCS_NAD27_Minnesota_South = 26793 PCS_NAD27_Mississippi_East = 26794 PCS_NAD27_Mississippi_West = 26795 PCS_NAD27_Missouri_East = 26796 PCS_NAD27_Missouri_Central = 26797 PCS_NAD27_Missouri_West = 26798 PCS_NAD_Michigan_Michigan_East = 26801 PCS_NAD_Michigan_Michigan_Old_Central = 26802 PCS_NAD_Michigan_Michigan_West = 26803 PCS_NAD83_UTM_zone_3N = 26903 PCS_NAD83_UTM_zone_4N = 26904 PCS_NAD83_UTM_zone_5N = 26905 PCS_NAD83_UTM_zone_6N = 26906 PCS_NAD83_UTM_zone_7N = 26907 PCS_NAD83_UTM_zone_8N = 26908 PCS_NAD83_UTM_zone_9N = 26909 PCS_NAD83_UTM_zone_10N = 26910 PCS_NAD83_UTM_zone_11N = 26911 PCS_NAD83_UTM_zone_12N = 26912 PCS_NAD83_UTM_zone_13N = 26913 PCS_NAD83_UTM_zone_14N = 26914 PCS_NAD83_UTM_zone_15N = 26915 PCS_NAD83_UTM_zone_16N = 26916 PCS_NAD83_UTM_zone_17N = 26917 PCS_NAD83_UTM_zone_18N = 26918 PCS_NAD83_UTM_zone_19N = 26919 PCS_NAD83_UTM_zone_20N = 26920 PCS_NAD83_UTM_zone_21N = 26921 PCS_NAD83_UTM_zone_22N = 26922 PCS_NAD83_UTM_zone_23N = 26923 PCS_NAD83_Alabama_East = 26929 PCS_NAD83_Alabama_West = 26930 PCS_NAD83_Alaska_zone_1 = 26931 PCS_NAD83_Alaska_zone_2 = 26932 PCS_NAD83_Alaska_zone_3 = 26933 PCS_NAD83_Alaska_zone_4 = 26934 PCS_NAD83_Alaska_zone_5 = 26935 PCS_NAD83_Alaska_zone_6 = 26936 PCS_NAD83_Alaska_zone_7 = 26937 PCS_NAD83_Alaska_zone_8 = 26938 PCS_NAD83_Alaska_zone_9 = 26939 PCS_NAD83_Alaska_zone_10 = 26940 PCS_NAD83_California_1 = 26941 PCS_NAD83_California_2 = 26942 PCS_NAD83_California_3 = 26943 PCS_NAD83_California_4 = 26944 PCS_NAD83_California_5 = 26945 PCS_NAD83_California_6 = 26946 PCS_NAD83_Arizona_East = 26948 PCS_NAD83_Arizona_Central = 26949 PCS_NAD83_Arizona_West = 26950 PCS_NAD83_Arkansas_North = 26951 PCS_NAD83_Arkansas_South = 26952 PCS_NAD83_Colorado_North = 26953 PCS_NAD83_Colorado_Central = 26954 PCS_NAD83_Colorado_South = 26955 PCS_NAD83_Connecticut = 26956 PCS_NAD83_Delaware = 26957 PCS_NAD83_Florida_East = 26958 PCS_NAD83_Florida_West = 26959 PCS_NAD83_Florida_North = 26960 PCS_NAD83_Hawaii_zone_1 = 26961 PCS_NAD83_Hawaii_zone_2 = 26962 PCS_NAD83_Hawaii_zone_3 = 26963 PCS_NAD83_Hawaii_zone_4 = 26964 PCS_NAD83_Hawaii_zone_5 = 26965 PCS_NAD83_Georgia_East = 26966 PCS_NAD83_Georgia_West = 26967 PCS_NAD83_Idaho_East = 26968 PCS_NAD83_Idaho_Central = 26969 PCS_NAD83_Idaho_West = 26970 PCS_NAD83_Illinois_East = 26971 PCS_NAD83_Illinois_West = 26972 PCS_NAD83_Indiana_East = 26973 PCS_NAD83_Indiana_West = 26974 PCS_NAD83_Iowa_North = 26975 PCS_NAD83_Iowa_South = 26976 PCS_NAD83_Kansas_North = 26977 PCS_NAD83_Kansas_South = 26978 PCS_NAD83_Kentucky_North = 26979 PCS_NAD83_Kentucky_South = 26980 PCS_NAD83_Louisiana_North = 26981 PCS_NAD83_Louisiana_South = 26982 PCS_NAD83_Maine_East = 26983 PCS_NAD83_Maine_West = 26984 PCS_NAD83_Maryland = 26985 PCS_NAD83_Massachusetts = 26986 PCS_NAD83_Massachusetts_Is = 26987 PCS_NAD83_Michigan_North = 26988 PCS_NAD83_Michigan_Central = 26989 PCS_NAD83_Michigan_South = 26990 PCS_NAD83_Minnesota_North = 26991 PCS_NAD83_Minnesota_Cent = 26992 PCS_NAD83_Minnesota_South = 26993 PCS_NAD83_Mississippi_East = 26994 PCS_NAD83_Mississippi_West = 26995 PCS_NAD83_Missouri_East = 26996 PCS_NAD83_Missouri_Central = 26997 PCS_NAD83_Missouri_West = 26998 PCS_Nahrwan_1967_UTM_38N = 27038 PCS_Nahrwan_1967_UTM_39N = 27039 PCS_Nahrwan_1967_UTM_40N = 27040 PCS_Naparima_UTM_20N = 27120 PCS_GD49_NZ_Map_Grid = 27200 PCS_GD49_North_Island_Grid = 27291 PCS_GD49_South_Island_Grid = 27292 PCS_Datum_73_UTM_zone_29N = 27429 PCS_ATF_Nord_de_Guerre = 27500 PCS_NTF_France_I = 27581 PCS_NTF_France_II = 27582 PCS_NTF_France_III = 27583 PCS_NTF_Nord_France = 27591 PCS_NTF_Centre_France = 27592 PCS_NTF_Sud_France = 27593 PCS_British_National_Grid = 27700 PCS_Point_Noire_UTM_32S = 28232 PCS_GDA94_MGA_zone_48 = 28348 PCS_GDA94_MGA_zone_49 = 28349 PCS_GDA94_MGA_zone_50 = 28350 PCS_GDA94_MGA_zone_51 = 28351 PCS_GDA94_MGA_zone_52 = 28352 PCS_GDA94_MGA_zone_53 = 28353 PCS_GDA94_MGA_zone_54 = 28354 PCS_GDA94_MGA_zone_55 = 28355 PCS_GDA94_MGA_zone_56 = 28356 PCS_GDA94_MGA_zone_57 = 28357 PCS_GDA94_MGA_zone_58 = 28358 PCS_Pulkovo_Gauss_zone_4 = 28404 PCS_Pulkovo_Gauss_zone_5 = 28405 PCS_Pulkovo_Gauss_zone_6 = 28406 PCS_Pulkovo_Gauss_zone_7 = 28407 PCS_Pulkovo_Gauss_zone_8 = 28408 PCS_Pulkovo_Gauss_zone_9 = 28409 PCS_Pulkovo_Gauss_zone_10 = 28410 PCS_Pulkovo_Gauss_zone_11 = 28411 PCS_Pulkovo_Gauss_zone_12 = 28412 PCS_Pulkovo_Gauss_zone_13 = 28413 PCS_Pulkovo_Gauss_zone_14 = 28414 PCS_Pulkovo_Gauss_zone_15 = 28415 PCS_Pulkovo_Gauss_zone_16 = 28416 PCS_Pulkovo_Gauss_zone_17 = 28417 PCS_Pulkovo_Gauss_zone_18 = 28418 PCS_Pulkovo_Gauss_zone_19 = 28419 PCS_Pulkovo_Gauss_zone_20 = 28420 PCS_Pulkovo_Gauss_zone_21 = 28421 PCS_Pulkovo_Gauss_zone_22 = 28422 PCS_Pulkovo_Gauss_zone_23 = 28423 PCS_Pulkovo_Gauss_zone_24 = 28424 PCS_Pulkovo_Gauss_zone_25 = 28425 PCS_Pulkovo_Gauss_zone_26 = 28426 PCS_Pulkovo_Gauss_zone_27 = 28427 PCS_Pulkovo_Gauss_zone_28 = 28428 PCS_Pulkovo_Gauss_zone_29 = 28429 PCS_Pulkovo_Gauss_zone_30 = 28430 PCS_Pulkovo_Gauss_zone_31 = 28431 PCS_Pulkovo_Gauss_zone_32 = 28432 PCS_Pulkovo_Gauss_4N = 28464 PCS_Pulkovo_Gauss_5N = 28465 PCS_Pulkovo_Gauss_6N = 28466 PCS_Pulkovo_Gauss_7N = 28467 PCS_Pulkovo_Gauss_8N = 28468 PCS_Pulkovo_Gauss_9N = 28469 PCS_Pulkovo_Gauss_10N = 28470 PCS_Pulkovo_Gauss_11N = 28471 PCS_Pulkovo_Gauss_12N = 28472 PCS_Pulkovo_Gauss_13N = 28473 PCS_Pulkovo_Gauss_14N = 28474 PCS_Pulkovo_Gauss_15N = 28475 PCS_Pulkovo_Gauss_16N = 28476 PCS_Pulkovo_Gauss_17N = 28477 PCS_Pulkovo_Gauss_18N = 28478 PCS_Pulkovo_Gauss_19N = 28479 PCS_Pulkovo_Gauss_20N = 28480 PCS_Pulkovo_Gauss_21N = 28481 PCS_Pulkovo_Gauss_22N = 28482 PCS_Pulkovo_Gauss_23N = 28483 PCS_Pulkovo_Gauss_24N = 28484 PCS_Pulkovo_Gauss_25N = 28485 PCS_Pulkovo_Gauss_26N = 28486 PCS_Pulkovo_Gauss_27N = 28487 PCS_Pulkovo_Gauss_28N = 28488 PCS_Pulkovo_Gauss_29N = 28489 PCS_Pulkovo_Gauss_30N = 28490 PCS_Pulkovo_Gauss_31N = 28491 PCS_Pulkovo_Gauss_32N = 28492 PCS_Qatar_National_Grid = 28600 PCS_RD_Netherlands_Old = 28991 PCS_RD_Netherlands_New = 28992 PCS_SAD69_UTM_zone_18N = 29118 PCS_SAD69_UTM_zone_19N = 29119 PCS_SAD69_UTM_zone_20N = 29120 PCS_SAD69_UTM_zone_21N = 29121 PCS_SAD69_UTM_zone_22N = 29122 PCS_SAD69_UTM_zone_17S = 29177 PCS_SAD69_UTM_zone_18S = 29178 PCS_SAD69_UTM_zone_19S = 29179 PCS_SAD69_UTM_zone_20S = 29180 PCS_SAD69_UTM_zone_21S = 29181 PCS_SAD69_UTM_zone_22S = 29182 PCS_SAD69_UTM_zone_23S = 29183 PCS_SAD69_UTM_zone_24S = 29184 PCS_SAD69_UTM_zone_25S = 29185 PCS_Sapper_Hill_UTM_20S = 29220 PCS_Sapper_Hill_UTM_21S = 29221 PCS_Schwarzeck_UTM_33S = 29333 PCS_Sudan_UTM_zone_35N = 29635 PCS_Sudan_UTM_zone_36N = 29636 PCS_Tananarive_Laborde = 29700 PCS_Tananarive_UTM_38S = 29738 PCS_Tananarive_UTM_39S = 29739 PCS_Timbalai_1948_Borneo = 29800 PCS_Timbalai_1948_UTM_49N = 29849 PCS_Timbalai_1948_UTM_50N = 29850 PCS_TM65_Irish_Nat_Grid = 29900 PCS_Trinidad_1903_Trinidad = 30200 PCS_TC_1948_UTM_zone_39N = 30339 PCS_TC_1948_UTM_zone_40N = 30340 PCS_Voirol_N_Algerie_ancien = 30491 PCS_Voirol_S_Algerie_ancien = 30492 PCS_Voirol_Unifie_N_Algerie = 30591 PCS_Voirol_Unifie_S_Algerie = 30592 PCS_Bern_1938_Swiss_New = 30600 PCS_Nord_Sahara_UTM_29N = 30729 PCS_Nord_Sahara_UTM_30N = 30730 PCS_Nord_Sahara_UTM_31N = 30731 PCS_Nord_Sahara_UTM_32N = 30732 PCS_Yoff_UTM_zone_28N = 31028 PCS_Zanderij_UTM_zone_21N = 31121 PCS_MGI_Austria_West = 31291 PCS_MGI_Austria_Central = 31292 PCS_MGI_Austria_East = 31293 PCS_Belge_Lambert_72 = 31300 PCS_DHDN_Germany_zone_1 = 31491 PCS_DHDN_Germany_zone_2 = 31492 PCS_DHDN_Germany_zone_3 = 31493 PCS_DHDN_Germany_zone_4 = 31494 PCS_DHDN_Germany_zone_5 = 31495 PCS_NAD27_Montana_North = 32001 PCS_NAD27_Montana_Central = 32002 PCS_NAD27_Montana_South = 32003 PCS_NAD27_Nebraska_North = 32005 PCS_NAD27_Nebraska_South = 32006 PCS_NAD27_Nevada_East = 32007 PCS_NAD27_Nevada_Central = 32008 PCS_NAD27_Nevada_West = 32009 PCS_NAD27_New_Hampshire = 32010 PCS_NAD27_New_Jersey = 32011 PCS_NAD27_New_Mexico_East = 32012 PCS_NAD27_New_Mexico_Cent = 32013 PCS_NAD27_New_Mexico_West = 32014 PCS_NAD27_New_York_East = 32015 PCS_NAD27_New_York_Central = 32016 PCS_NAD27_New_York_West = 32017 PCS_NAD27_New_York_Long_Is = 32018 PCS_NAD27_North_Carolina = 32019 PCS_NAD27_North_Dakota_N = 32020 PCS_NAD27_North_Dakota_S = 32021 PCS_NAD27_Ohio_North = 32022 PCS_NAD27_Ohio_South = 32023 PCS_NAD27_Oklahoma_North = 32024 PCS_NAD27_Oklahoma_South = 32025 PCS_NAD27_Oregon_North = 32026 PCS_NAD27_Oregon_South = 32027 PCS_NAD27_Pennsylvania_N = 32028 PCS_NAD27_Pennsylvania_S = 32029 PCS_NAD27_Rhode_Island = 32030 PCS_NAD27_South_Carolina_N = 32031 PCS_NAD27_South_Carolina_S = 32033 PCS_NAD27_South_Dakota_N = 32034 PCS_NAD27_South_Dakota_S = 32035 PCS_NAD27_Tennessee = 32036 PCS_NAD27_Texas_North = 32037 PCS_NAD27_Texas_North_Cen = 32038 PCS_NAD27_Texas_Central = 32039 PCS_NAD27_Texas_South_Cen = 32040 PCS_NAD27_Texas_South = 32041 PCS_NAD27_Utah_North = 32042 PCS_NAD27_Utah_Central = 32043 PCS_NAD27_Utah_South = 32044 PCS_NAD27_Vermont = 32045 PCS_NAD27_Virginia_North = 32046 PCS_NAD27_Virginia_South = 32047 PCS_NAD27_Washington_North = 32048 PCS_NAD27_Washington_South = 32049 PCS_NAD27_West_Virginia_N = 32050 PCS_NAD27_West_Virginia_S = 32051 PCS_NAD27_Wisconsin_North = 32052 PCS_NAD27_Wisconsin_Cen = 32053 PCS_NAD27_Wisconsin_South = 32054 PCS_NAD27_Wyoming_East = 32055 PCS_NAD27_Wyoming_E_Cen = 32056 PCS_NAD27_Wyoming_W_Cen = 32057 PCS_NAD27_Wyoming_West = 32058 PCS_NAD27_Puerto_Rico = 32059 PCS_NAD27_St_Croix = 32060 PCS_NAD83_Montana = 32100 PCS_NAD83_Nebraska = 32104 PCS_NAD83_Nevada_East = 32107 PCS_NAD83_Nevada_Central = 32108 PCS_NAD83_Nevada_West = 32109 PCS_NAD83_New_Hampshire = 32110 PCS_NAD83_New_Jersey = 32111 PCS_NAD83_New_Mexico_East = 32112 PCS_NAD83_New_Mexico_Cent = 32113 PCS_NAD83_New_Mexico_West = 32114 PCS_NAD83_New_York_East = 32115 PCS_NAD83_New_York_Central = 32116 PCS_NAD83_New_York_West = 32117 PCS_NAD83_New_York_Long_Is = 32118 PCS_NAD83_North_Carolina = 32119 PCS_NAD83_North_Dakota_N = 32120 PCS_NAD83_North_Dakota_S = 32121 PCS_NAD83_Ohio_North = 32122 PCS_NAD83_Ohio_South = 32123 PCS_NAD83_Oklahoma_North = 32124 PCS_NAD83_Oklahoma_South = 32125 PCS_NAD83_Oregon_North = 32126 PCS_NAD83_Oregon_South = 32127 PCS_NAD83_Pennsylvania_N = 32128 PCS_NAD83_Pennsylvania_S = 32129 PCS_NAD83_Rhode_Island = 32130 PCS_NAD83_South_Carolina = 32133 PCS_NAD83_South_Dakota_N = 32134 PCS_NAD83_South_Dakota_S = 32135 PCS_NAD83_Tennessee = 32136 PCS_NAD83_Texas_North = 32137 PCS_NAD83_Texas_North_Cen = 32138 PCS_NAD83_Texas_Central = 32139 PCS_NAD83_Texas_South_Cen = 32140 PCS_NAD83_Texas_South = 32141 PCS_NAD83_Utah_North = 32142 PCS_NAD83_Utah_Central = 32143 PCS_NAD83_Utah_South = 32144 PCS_NAD83_Vermont = 32145 PCS_NAD83_Virginia_North = 32146 PCS_NAD83_Virginia_South = 32147 PCS_NAD83_Washington_North = 32148 PCS_NAD83_Washington_South = 32149 PCS_NAD83_West_Virginia_N = 32150 PCS_NAD83_West_Virginia_S = 32151 PCS_NAD83_Wisconsin_North = 32152 PCS_NAD83_Wisconsin_Cen = 32153 PCS_NAD83_Wisconsin_South = 32154 PCS_NAD83_Wyoming_East = 32155 PCS_NAD83_Wyoming_E_Cen = 32156 PCS_NAD83_Wyoming_W_Cen = 32157 PCS_NAD83_Wyoming_West = 32158 PCS_NAD83_Puerto_Rico_Virgin_Is = 32161 PCS_WGS72_UTM_zone_1N = 32201 PCS_WGS72_UTM_zone_2N = 32202 PCS_WGS72_UTM_zone_3N = 32203 PCS_WGS72_UTM_zone_4N = 32204 PCS_WGS72_UTM_zone_5N = 32205 PCS_WGS72_UTM_zone_6N = 32206 PCS_WGS72_UTM_zone_7N = 32207 PCS_WGS72_UTM_zone_8N = 32208 PCS_WGS72_UTM_zone_9N = 32209 PCS_WGS72_UTM_zone_10N = 32210 PCS_WGS72_UTM_zone_11N = 32211 PCS_WGS72_UTM_zone_12N = 32212 PCS_WGS72_UTM_zone_13N = 32213 PCS_WGS72_UTM_zone_14N = 32214 PCS_WGS72_UTM_zone_15N = 32215 PCS_WGS72_UTM_zone_16N = 32216 PCS_WGS72_UTM_zone_17N = 32217 PCS_WGS72_UTM_zone_18N = 32218 PCS_WGS72_UTM_zone_19N = 32219 PCS_WGS72_UTM_zone_20N = 32220 PCS_WGS72_UTM_zone_21N = 32221 PCS_WGS72_UTM_zone_22N = 32222 PCS_WGS72_UTM_zone_23N = 32223 PCS_WGS72_UTM_zone_24N = 32224 PCS_WGS72_UTM_zone_25N = 32225 PCS_WGS72_UTM_zone_26N = 32226 PCS_WGS72_UTM_zone_27N = 32227 PCS_WGS72_UTM_zone_28N = 32228 PCS_WGS72_UTM_zone_29N = 32229 PCS_WGS72_UTM_zone_30N = 32230 PCS_WGS72_UTM_zone_31N = 32231 PCS_WGS72_UTM_zone_32N = 32232 PCS_WGS72_UTM_zone_33N = 32233 PCS_WGS72_UTM_zone_34N = 32234 PCS_WGS72_UTM_zone_35N = 32235 PCS_WGS72_UTM_zone_36N = 32236 PCS_WGS72_UTM_zone_37N = 32237 PCS_WGS72_UTM_zone_38N = 32238 PCS_WGS72_UTM_zone_39N = 32239 PCS_WGS72_UTM_zone_40N = 32240 PCS_WGS72_UTM_zone_41N = 32241 PCS_WGS72_UTM_zone_42N = 32242 PCS_WGS72_UTM_zone_43N = 32243 PCS_WGS72_UTM_zone_44N = 32244 PCS_WGS72_UTM_zone_45N = 32245 PCS_WGS72_UTM_zone_46N = 32246 PCS_WGS72_UTM_zone_47N = 32247 PCS_WGS72_UTM_zone_48N = 32248 PCS_WGS72_UTM_zone_49N = 32249 PCS_WGS72_UTM_zone_50N = 32250 PCS_WGS72_UTM_zone_51N = 32251 PCS_WGS72_UTM_zone_52N = 32252 PCS_WGS72_UTM_zone_53N = 32253 PCS_WGS72_UTM_zone_54N = 32254 PCS_WGS72_UTM_zone_55N = 32255 PCS_WGS72_UTM_zone_56N = 32256 PCS_WGS72_UTM_zone_57N = 32257 PCS_WGS72_UTM_zone_58N = 32258 PCS_WGS72_UTM_zone_59N = 32259 PCS_WGS72_UTM_zone_60N = 32260 PCS_WGS72_UTM_zone_1S = 32301 PCS_WGS72_UTM_zone_2S = 32302 PCS_WGS72_UTM_zone_3S = 32303 PCS_WGS72_UTM_zone_4S = 32304 PCS_WGS72_UTM_zone_5S = 32305 PCS_WGS72_UTM_zone_6S = 32306 PCS_WGS72_UTM_zone_7S = 32307 PCS_WGS72_UTM_zone_8S = 32308 PCS_WGS72_UTM_zone_9S = 32309 PCS_WGS72_UTM_zone_10S = 32310 PCS_WGS72_UTM_zone_11S = 32311 PCS_WGS72_UTM_zone_12S = 32312 PCS_WGS72_UTM_zone_13S = 32313 PCS_WGS72_UTM_zone_14S = 32314 PCS_WGS72_UTM_zone_15S = 32315 PCS_WGS72_UTM_zone_16S = 32316 PCS_WGS72_UTM_zone_17S = 32317 PCS_WGS72_UTM_zone_18S = 32318 PCS_WGS72_UTM_zone_19S = 32319 PCS_WGS72_UTM_zone_20S = 32320 PCS_WGS72_UTM_zone_21S = 32321 PCS_WGS72_UTM_zone_22S = 32322 PCS_WGS72_UTM_zone_23S = 32323 PCS_WGS72_UTM_zone_24S = 32324 PCS_WGS72_UTM_zone_25S = 32325 PCS_WGS72_UTM_zone_26S = 32326 PCS_WGS72_UTM_zone_27S = 32327 PCS_WGS72_UTM_zone_28S = 32328 PCS_WGS72_UTM_zone_29S = 32329 PCS_WGS72_UTM_zone_30S = 32330 PCS_WGS72_UTM_zone_31S = 32331 PCS_WGS72_UTM_zone_32S = 32332 PCS_WGS72_UTM_zone_33S = 32333 PCS_WGS72_UTM_zone_34S = 32334 PCS_WGS72_UTM_zone_35S = 32335 PCS_WGS72_UTM_zone_36S = 32336 PCS_WGS72_UTM_zone_37S = 32337 PCS_WGS72_UTM_zone_38S = 32338 PCS_WGS72_UTM_zone_39S = 32339 PCS_WGS72_UTM_zone_40S = 32340 PCS_WGS72_UTM_zone_41S = 32341 PCS_WGS72_UTM_zone_42S = 32342 PCS_WGS72_UTM_zone_43S = 32343 PCS_WGS72_UTM_zone_44S = 32344 PCS_WGS72_UTM_zone_45S = 32345 PCS_WGS72_UTM_zone_46S = 32346 PCS_WGS72_UTM_zone_47S = 32347 PCS_WGS72_UTM_zone_48S = 32348 PCS_WGS72_UTM_zone_49S = 32349 PCS_WGS72_UTM_zone_50S = 32350 PCS_WGS72_UTM_zone_51S = 32351 PCS_WGS72_UTM_zone_52S = 32352 PCS_WGS72_UTM_zone_53S = 32353 PCS_WGS72_UTM_zone_54S = 32354 PCS_WGS72_UTM_zone_55S = 32355 PCS_WGS72_UTM_zone_56S = 32356 PCS_WGS72_UTM_zone_57S = 32357 PCS_WGS72_UTM_zone_58S = 32358 PCS_WGS72_UTM_zone_59S = 32359 PCS_WGS72_UTM_zone_60S = 32360 PCS_WGS72BE_UTM_zone_1N = 32401 PCS_WGS72BE_UTM_zone_2N = 32402 PCS_WGS72BE_UTM_zone_3N = 32403 PCS_WGS72BE_UTM_zone_4N = 32404 PCS_WGS72BE_UTM_zone_5N = 32405 PCS_WGS72BE_UTM_zone_6N = 32406 PCS_WGS72BE_UTM_zone_7N = 32407 PCS_WGS72BE_UTM_zone_8N = 32408 PCS_WGS72BE_UTM_zone_9N = 32409 PCS_WGS72BE_UTM_zone_10N = 32410 PCS_WGS72BE_UTM_zone_11N = 32411 PCS_WGS72BE_UTM_zone_12N = 32412 PCS_WGS72BE_UTM_zone_13N = 32413 PCS_WGS72BE_UTM_zone_14N = 32414 PCS_WGS72BE_UTM_zone_15N = 32415 PCS_WGS72BE_UTM_zone_16N = 32416 PCS_WGS72BE_UTM_zone_17N = 32417 PCS_WGS72BE_UTM_zone_18N = 32418 PCS_WGS72BE_UTM_zone_19N = 32419 PCS_WGS72BE_UTM_zone_20N = 32420 PCS_WGS72BE_UTM_zone_21N = 32421 PCS_WGS72BE_UTM_zone_22N = 32422 PCS_WGS72BE_UTM_zone_23N = 32423 PCS_WGS72BE_UTM_zone_24N = 32424 PCS_WGS72BE_UTM_zone_25N = 32425 PCS_WGS72BE_UTM_zone_26N = 32426 PCS_WGS72BE_UTM_zone_27N = 32427 PCS_WGS72BE_UTM_zone_28N = 32428 PCS_WGS72BE_UTM_zone_29N = 32429 PCS_WGS72BE_UTM_zone_30N = 32430 PCS_WGS72BE_UTM_zone_31N = 32431 PCS_WGS72BE_UTM_zone_32N = 32432 PCS_WGS72BE_UTM_zone_33N = 32433 PCS_WGS72BE_UTM_zone_34N = 32434 PCS_WGS72BE_UTM_zone_35N = 32435 PCS_WGS72BE_UTM_zone_36N = 32436 PCS_WGS72BE_UTM_zone_37N = 32437 PCS_WGS72BE_UTM_zone_38N = 32438 PCS_WGS72BE_UTM_zone_39N = 32439 PCS_WGS72BE_UTM_zone_40N = 32440 PCS_WGS72BE_UTM_zone_41N = 32441 PCS_WGS72BE_UTM_zone_42N = 32442 PCS_WGS72BE_UTM_zone_43N = 32443 PCS_WGS72BE_UTM_zone_44N = 32444 PCS_WGS72BE_UTM_zone_45N = 32445 PCS_WGS72BE_UTM_zone_46N = 32446 PCS_WGS72BE_UTM_zone_47N = 32447 PCS_WGS72BE_UTM_zone_48N = 32448 PCS_WGS72BE_UTM_zone_49N = 32449 PCS_WGS72BE_UTM_zone_50N = 32450 PCS_WGS72BE_UTM_zone_51N = 32451 PCS_WGS72BE_UTM_zone_52N = 32452 PCS_WGS72BE_UTM_zone_53N = 32453 PCS_WGS72BE_UTM_zone_54N = 32454 PCS_WGS72BE_UTM_zone_55N = 32455 PCS_WGS72BE_UTM_zone_56N = 32456 PCS_WGS72BE_UTM_zone_57N = 32457 PCS_WGS72BE_UTM_zone_58N = 32458 PCS_WGS72BE_UTM_zone_59N = 32459 PCS_WGS72BE_UTM_zone_60N = 32460 PCS_WGS72BE_UTM_zone_1S = 32501 PCS_WGS72BE_UTM_zone_2S = 32502 PCS_WGS72BE_UTM_zone_3S = 32503 PCS_WGS72BE_UTM_zone_4S = 32504 PCS_WGS72BE_UTM_zone_5S = 32505 PCS_WGS72BE_UTM_zone_6S = 32506 PCS_WGS72BE_UTM_zone_7S = 32507 PCS_WGS72BE_UTM_zone_8S = 32508 PCS_WGS72BE_UTM_zone_9S = 32509 PCS_WGS72BE_UTM_zone_10S = 32510 PCS_WGS72BE_UTM_zone_11S = 32511 PCS_WGS72BE_UTM_zone_12S = 32512 PCS_WGS72BE_UTM_zone_13S = 32513 PCS_WGS72BE_UTM_zone_14S = 32514 PCS_WGS72BE_UTM_zone_15S = 32515 PCS_WGS72BE_UTM_zone_16S = 32516 PCS_WGS72BE_UTM_zone_17S = 32517 PCS_WGS72BE_UTM_zone_18S = 32518 PCS_WGS72BE_UTM_zone_19S = 32519 PCS_WGS72BE_UTM_zone_20S = 32520 PCS_WGS72BE_UTM_zone_21S = 32521 PCS_WGS72BE_UTM_zone_22S = 32522 PCS_WGS72BE_UTM_zone_23S = 32523 PCS_WGS72BE_UTM_zone_24S = 32524 PCS_WGS72BE_UTM_zone_25S = 32525 PCS_WGS72BE_UTM_zone_26S = 32526 PCS_WGS72BE_UTM_zone_27S = 32527 PCS_WGS72BE_UTM_zone_28S = 32528 PCS_WGS72BE_UTM_zone_29S = 32529 PCS_WGS72BE_UTM_zone_30S = 32530 PCS_WGS72BE_UTM_zone_31S = 32531 PCS_WGS72BE_UTM_zone_32S = 32532 PCS_WGS72BE_UTM_zone_33S = 32533 PCS_WGS72BE_UTM_zone_34S = 32534 PCS_WGS72BE_UTM_zone_35S = 32535 PCS_WGS72BE_UTM_zone_36S = 32536 PCS_WGS72BE_UTM_zone_37S = 32537 PCS_WGS72BE_UTM_zone_38S = 32538 PCS_WGS72BE_UTM_zone_39S = 32539 PCS_WGS72BE_UTM_zone_40S = 32540 PCS_WGS72BE_UTM_zone_41S = 32541 PCS_WGS72BE_UTM_zone_42S = 32542 PCS_WGS72BE_UTM_zone_43S = 32543 PCS_WGS72BE_UTM_zone_44S = 32544 PCS_WGS72BE_UTM_zone_45S = 32545 PCS_WGS72BE_UTM_zone_46S = 32546 PCS_WGS72BE_UTM_zone_47S = 32547 PCS_WGS72BE_UTM_zone_48S = 32548 PCS_WGS72BE_UTM_zone_49S = 32549 PCS_WGS72BE_UTM_zone_50S = 32550 PCS_WGS72BE_UTM_zone_51S = 32551 PCS_WGS72BE_UTM_zone_52S = 32552 PCS_WGS72BE_UTM_zone_53S = 32553 PCS_WGS72BE_UTM_zone_54S = 32554 PCS_WGS72BE_UTM_zone_55S = 32555 PCS_WGS72BE_UTM_zone_56S = 32556 PCS_WGS72BE_UTM_zone_57S = 32557 PCS_WGS72BE_UTM_zone_58S = 32558 PCS_WGS72BE_UTM_zone_59S = 32559 PCS_WGS72BE_UTM_zone_60S = 32560 PCS_WGS84_UTM_zone_1N = 32601 PCS_WGS84_UTM_zone_2N = 32602 PCS_WGS84_UTM_zone_3N = 32603 PCS_WGS84_UTM_zone_4N = 32604 PCS_WGS84_UTM_zone_5N = 32605 PCS_WGS84_UTM_zone_6N = 32606 PCS_WGS84_UTM_zone_7N = 32607 PCS_WGS84_UTM_zone_8N = 32608 PCS_WGS84_UTM_zone_9N = 32609 PCS_WGS84_UTM_zone_10N = 32610 PCS_WGS84_UTM_zone_11N = 32611 PCS_WGS84_UTM_zone_12N = 32612 PCS_WGS84_UTM_zone_13N = 32613 PCS_WGS84_UTM_zone_14N = 32614 PCS_WGS84_UTM_zone_15N = 32615 PCS_WGS84_UTM_zone_16N = 32616 PCS_WGS84_UTM_zone_17N = 32617 PCS_WGS84_UTM_zone_18N = 32618 PCS_WGS84_UTM_zone_19N = 32619 PCS_WGS84_UTM_zone_20N = 32620 PCS_WGS84_UTM_zone_21N = 32621 PCS_WGS84_UTM_zone_22N = 32622 PCS_WGS84_UTM_zone_23N = 32623 PCS_WGS84_UTM_zone_24N = 32624 PCS_WGS84_UTM_zone_25N = 32625 PCS_WGS84_UTM_zone_26N = 32626 PCS_WGS84_UTM_zone_27N = 32627 PCS_WGS84_UTM_zone_28N = 32628 PCS_WGS84_UTM_zone_29N = 32629 PCS_WGS84_UTM_zone_30N = 32630 PCS_WGS84_UTM_zone_31N = 32631 PCS_WGS84_UTM_zone_32N = 32632 PCS_WGS84_UTM_zone_33N = 32633 PCS_WGS84_UTM_zone_34N = 32634 PCS_WGS84_UTM_zone_35N = 32635 PCS_WGS84_UTM_zone_36N = 32636 PCS_WGS84_UTM_zone_37N = 32637 PCS_WGS84_UTM_zone_38N = 32638 PCS_WGS84_UTM_zone_39N = 32639 PCS_WGS84_UTM_zone_40N = 32640 PCS_WGS84_UTM_zone_41N = 32641 PCS_WGS84_UTM_zone_42N = 32642 PCS_WGS84_UTM_zone_43N = 32643 PCS_WGS84_UTM_zone_44N = 32644 PCS_WGS84_UTM_zone_45N = 32645 PCS_WGS84_UTM_zone_46N = 32646 PCS_WGS84_UTM_zone_47N = 32647 PCS_WGS84_UTM_zone_48N = 32648 PCS_WGS84_UTM_zone_49N = 32649 PCS_WGS84_UTM_zone_50N = 32650 PCS_WGS84_UTM_zone_51N = 32651 PCS_WGS84_UTM_zone_52N = 32652 PCS_WGS84_UTM_zone_53N = 32653 PCS_WGS84_UTM_zone_54N = 32654 PCS_WGS84_UTM_zone_55N = 32655 PCS_WGS84_UTM_zone_56N = 32656 PCS_WGS84_UTM_zone_57N = 32657 PCS_WGS84_UTM_zone_58N = 32658 PCS_WGS84_UTM_zone_59N = 32659 PCS_WGS84_UTM_zone_60N = 32660 PCS_WGS84_UTM_zone_1S = 32701 PCS_WGS84_UTM_zone_2S = 32702 PCS_WGS84_UTM_zone_3S = 32703 PCS_WGS84_UTM_zone_4S = 32704 PCS_WGS84_UTM_zone_5S = 32705 PCS_WGS84_UTM_zone_6S = 32706 PCS_WGS84_UTM_zone_7S = 32707 PCS_WGS84_UTM_zone_8S = 32708 PCS_WGS84_UTM_zone_9S = 32709 PCS_WGS84_UTM_zone_10S = 32710 PCS_WGS84_UTM_zone_11S = 32711 PCS_WGS84_UTM_zone_12S = 32712 PCS_WGS84_UTM_zone_13S = 32713 PCS_WGS84_UTM_zone_14S = 32714 PCS_WGS84_UTM_zone_15S = 32715 PCS_WGS84_UTM_zone_16S = 32716 PCS_WGS84_UTM_zone_17S = 32717 PCS_WGS84_UTM_zone_18S = 32718 PCS_WGS84_UTM_zone_19S = 32719 PCS_WGS84_UTM_zone_20S = 32720 PCS_WGS84_UTM_zone_21S = 32721 PCS_WGS84_UTM_zone_22S = 32722 PCS_WGS84_UTM_zone_23S = 32723 PCS_WGS84_UTM_zone_24S = 32724 PCS_WGS84_UTM_zone_25S = 32725 PCS_WGS84_UTM_zone_26S = 32726 PCS_WGS84_UTM_zone_27S = 32727 PCS_WGS84_UTM_zone_28S = 32728 PCS_WGS84_UTM_zone_29S = 32729 PCS_WGS84_UTM_zone_30S = 32730 PCS_WGS84_UTM_zone_31S = 32731 PCS_WGS84_UTM_zone_32S = 32732 PCS_WGS84_UTM_zone_33S = 32733 PCS_WGS84_UTM_zone_34S = 32734 PCS_WGS84_UTM_zone_35S = 32735 PCS_WGS84_UTM_zone_36S = 32736 PCS_WGS84_UTM_zone_37S = 32737 PCS_WGS84_UTM_zone_38S = 32738 PCS_WGS84_UTM_zone_39S = 32739 PCS_WGS84_UTM_zone_40S = 32740 PCS_WGS84_UTM_zone_41S = 32741 PCS_WGS84_UTM_zone_42S = 32742 PCS_WGS84_UTM_zone_43S = 32743 PCS_WGS84_UTM_zone_44S = 32744 PCS_WGS84_UTM_zone_45S = 32745 PCS_WGS84_UTM_zone_46S = 32746 PCS_WGS84_UTM_zone_47S = 32747 PCS_WGS84_UTM_zone_48S = 32748 PCS_WGS84_UTM_zone_49S = 32749 PCS_WGS84_UTM_zone_50S = 32750 PCS_WGS84_UTM_zone_51S = 32751 PCS_WGS84_UTM_zone_52S = 32752 PCS_WGS84_UTM_zone_53S = 32753 PCS_WGS84_UTM_zone_54S = 32754 PCS_WGS84_UTM_zone_55S = 32755 PCS_WGS84_UTM_zone_56S = 32756 PCS_WGS84_UTM_zone_57S = 32757 PCS_WGS84_UTM_zone_58S = 32758 PCS_WGS84_UTM_zone_59S = 32759 PCS_WGS84_UTM_zone_60S = 32760 +----------------------------------+ 6.3.3.2 Projection Codes Note: Projections do not include GCS/datum definitions. If possible, use the PCS code for standard projected coordinate systems, and use this code only if nonstandard datums are required. Ranges: 0 = undefined [ 1, 9999] = Obsolete EPSG/POSC Projection codes [10000, 19999] = EPSG/POSC Projection codes 32767 = user-defined [32768, 65535] = Private User Implementations Special Ranges: US State Plane Format: 1sszz where ss is USC&GS State code zz is USC&GS zone code for NAD27 zones zz is (USC&GS zone code + 30) for NAD83 zones Larger zoned systems (16000-17999) UTM (North) Format: 160zz UTM (South) Format: 161zz zoned Universal Gauss-Kruger Format: 162zz Universal Gauss-Kruger (unzoned) Format: 163zz Australian Map Grid Format: 174zz Southern African STM Format: 175zz Smaller zoned systems: Format: 18ssz where ss is sequential system number z is zone code Single zone projections Format: 199ss where ss is sequential system number Values: Proj_Alabama_CS27_East = 10101 Proj_Alabama_CS27_West = 10102 Proj_Alabama_CS83_East = 10131 Proj_Alabama_CS83_West = 10132 Proj_Arizona_Coordinate_System_east = 10201 Proj_Arizona_Coordinate_System_Central = 10202 Proj_Arizona_Coordinate_System_west = 10203 Proj_Arizona_CS83_east = 10231 Proj_Arizona_CS83_Central = 10232 Proj_Arizona_CS83_west = 10233 Proj_Arkansas_CS27_North = 10301 Proj_Arkansas_CS27_South = 10302 Proj_Arkansas_CS83_North = 10331 Proj_Arkansas_CS83_South = 10332 Proj_California_CS27_I = 10401 Proj_California_CS27_II = 10402 Proj_California_CS27_III = 10403 Proj_California_CS27_IV = 10404 Proj_California_CS27_V = 10405 Proj_California_CS27_VI = 10406 Proj_California_CS27_VII = 10407 Proj_California_CS83_1 = 10431 Proj_California_CS83_2 = 10432 Proj_California_CS83_3 = 10433 Proj_California_CS83_4 = 10434 Proj_California_CS83_5 = 10435 Proj_California_CS83_6 = 10436 Proj_Colorado_CS27_North = 10501 Proj_Colorado_CS27_Central = 10502 Proj_Colorado_CS27_South = 10503 Proj_Colorado_CS83_North = 10531 Proj_Colorado_CS83_Central = 10532 Proj_Colorado_CS83_South = 10533 Proj_Connecticut_CS27 = 10600 Proj_Connecticut_CS83 = 10630 Proj_Delaware_CS27 = 10700 Proj_Delaware_CS83 = 10730 Proj_Florida_CS27_East = 10901 Proj_Florida_CS27_West = 10902 Proj_Florida_CS27_North = 10903 Proj_Florida_CS83_East = 10931 Proj_Florida_CS83_West = 10932 Proj_Florida_CS83_North = 10933 Proj_Georgia_CS27_East = 11001 Proj_Georgia_CS27_West = 11002 Proj_Georgia_CS83_East = 11031 Proj_Georgia_CS83_West = 11032 Proj_Idaho_CS27_East = 11101 Proj_Idaho_CS27_Central = 11102 Proj_Idaho_CS27_West = 11103 Proj_Idaho_CS83_East = 11131 Proj_Idaho_CS83_Central = 11132 Proj_Idaho_CS83_West = 11133 Proj_Illinois_CS27_East = 11201 Proj_Illinois_CS27_West = 11202 Proj_Illinois_CS83_East = 11231 Proj_Illinois_CS83_West = 11232 Proj_Indiana_CS27_East = 11301 Proj_Indiana_CS27_West = 11302 Proj_Indiana_CS83_East = 11331 Proj_Indiana_CS83_West = 11332 Proj_Iowa_CS27_North = 11401 Proj_Iowa_CS27_South = 11402 Proj_Iowa_CS83_North = 11431 Proj_Iowa_CS83_South = 11432 Proj_Kansas_CS27_North = 11501 Proj_Kansas_CS27_South = 11502 Proj_Kansas_CS83_North = 11531 Proj_Kansas_CS83_South = 11532 Proj_Kentucky_CS27_North = 11601 Proj_Kentucky_CS27_South = 11602 Proj_Kentucky_CS83_North = 11631 Proj_Kentucky_CS83_South = 11632 Proj_Louisiana_CS27_North = 11701 Proj_Louisiana_CS27_South = 11702 Proj_Louisiana_CS83_North = 11731 Proj_Louisiana_CS83_South = 11732 Proj_Maine_CS27_East = 11801 Proj_Maine_CS27_West = 11802 Proj_Maine_CS83_East = 11831 Proj_Maine_CS83_West = 11832 Proj_Maryland_CS27 = 11900 Proj_Maryland_CS83 = 11930 Proj_Massachusetts_CS27_Mainland = 12001 Proj_Massachusetts_CS27_Island = 12002 Proj_Massachusetts_CS83_Mainland = 12031 Proj_Massachusetts_CS83_Island = 12032 Proj_Michigan_State_Plane_East = 12101 Proj_Michigan_State_Plane_Old_Central = 12102 Proj_Michigan_State_Plane_West = 12103 Proj_Michigan_CS27_North = 12111 Proj_Michigan_CS27_Central = 12112 Proj_Michigan_CS27_South = 12113 Proj_Michigan_CS83_North = 12141 Proj_Michigan_CS83_Central = 12142 Proj_Michigan_CS83_South = 12143 Proj_Minnesota_CS27_North = 12201 Proj_Minnesota_CS27_Central = 12202 Proj_Minnesota_CS27_South = 12203 Proj_Minnesota_CS83_North = 12231 Proj_Minnesota_CS83_Central = 12232 Proj_Minnesota_CS83_South = 12233 Proj_Mississippi_CS27_East = 12301 Proj_Mississippi_CS27_West = 12302 Proj_Mississippi_CS83_East = 12331 Proj_Mississippi_CS83_West = 12332 Proj_Missouri_CS27_East = 12401 Proj_Missouri_CS27_Central = 12402 Proj_Missouri_CS27_West = 12403 Proj_Missouri_CS83_East = 12431 Proj_Missouri_CS83_Central = 12432 Proj_Missouri_CS83_West = 12433 Proj_Montana_CS27_North = 12501 Proj_Montana_CS27_Central = 12502 Proj_Montana_CS27_South = 12503 Proj_Montana_CS83 = 12530 Proj_Nebraska_CS27_North = 12601 Proj_Nebraska_CS27_South = 12602 Proj_Nebraska_CS83 = 12630 Proj_Nevada_CS27_East = 12701 Proj_Nevada_CS27_Central = 12702 Proj_Nevada_CS27_West = 12703 Proj_Nevada_CS83_East = 12731 Proj_Nevada_CS83_Central = 12732 Proj_Nevada_CS83_West = 12733 Proj_New_Hampshire_CS27 = 12800 Proj_New_Hampshire_CS83 = 12830 Proj_New_Jersey_CS27 = 12900 Proj_New_Jersey_CS83 = 12930 Proj_New_Mexico_CS27_East = 13001 Proj_New_Mexico_CS27_Central = 13002 Proj_New_Mexico_CS27_West = 13003 Proj_New_Mexico_CS83_East = 13031 Proj_New_Mexico_CS83_Central = 13032 Proj_New_Mexico_CS83_West = 13033 Proj_New_York_CS27_East = 13101 Proj_New_York_CS27_Central = 13102 Proj_New_York_CS27_West = 13103 Proj_New_York_CS27_Long_Island = 13104 Proj_New_York_CS83_East = 13131 Proj_New_York_CS83_Central = 13132 Proj_New_York_CS83_West = 13133 Proj_New_York_CS83_Long_Island = 13134 Proj_North_Carolina_CS27 = 13200 Proj_North_Carolina_CS83 = 13230 Proj_North_Dakota_CS27_North = 13301 Proj_North_Dakota_CS27_South = 13302 Proj_North_Dakota_CS83_North = 13331 Proj_North_Dakota_CS83_South = 13332 Proj_Ohio_CS27_North = 13401 Proj_Ohio_CS27_South = 13402 Proj_Ohio_CS83_North = 13431 Proj_Ohio_CS83_South = 13432 Proj_Oklahoma_CS27_North = 13501 Proj_Oklahoma_CS27_South = 13502 Proj_Oklahoma_CS83_North = 13531 Proj_Oklahoma_CS83_South = 13532 Proj_Oregon_CS27_North = 13601 Proj_Oregon_CS27_South = 13602 Proj_Oregon_CS83_North = 13631 Proj_Oregon_CS83_South = 13632 Proj_Pennsylvania_CS27_North = 13701 Proj_Pennsylvania_CS27_South = 13702 Proj_Pennsylvania_CS83_North = 13731 Proj_Pennsylvania_CS83_South = 13732 Proj_Rhode_Island_CS27 = 13800 Proj_Rhode_Island_CS83 = 13830 Proj_South_Carolina_CS27_North = 13901 Proj_South_Carolina_CS27_South = 13902 Proj_South_Carolina_CS83 = 13930 Proj_South_Dakota_CS27_North = 14001 Proj_South_Dakota_CS27_South = 14002 Proj_South_Dakota_CS83_North = 14031 Proj_South_Dakota_CS83_South = 14032 Proj_Tennessee_CS27 = 14100 Proj_Tennessee_CS83 = 14130 Proj_Texas_CS27_North = 14201 Proj_Texas_CS27_North_Central = 14202 Proj_Texas_CS27_Central = 14203 Proj_Texas_CS27_South_Central = 14204 Proj_Texas_CS27_South = 14205 Proj_Texas_CS83_North = 14231 Proj_Texas_CS83_North_Central = 14232 Proj_Texas_CS83_Central = 14233 Proj_Texas_CS83_South_Central = 14234 Proj_Texas_CS83_South = 14235 Proj_Utah_CS27_North = 14301 Proj_Utah_CS27_Central = 14302 Proj_Utah_CS27_South = 14303 Proj_Utah_CS83_North = 14331 Proj_Utah_CS83_Central = 14332 Proj_Utah_CS83_South = 14333 Proj_Vermont_CS27 = 14400 Proj_Vermont_CS83 = 14430 Proj_Virginia_CS27_North = 14501 Proj_Virginia_CS27_South = 14502 Proj_Virginia_CS83_North = 14531 Proj_Virginia_CS83_South = 14532 Proj_Washington_CS27_North = 14601 Proj_Washington_CS27_South = 14602 Proj_Washington_CS83_North = 14631 Proj_Washington_CS83_South = 14632 Proj_West_Virginia_CS27_North = 14701 Proj_West_Virginia_CS27_South = 14702 Proj_West_Virginia_CS83_North = 14731 Proj_West_Virginia_CS83_South = 14732 Proj_Wisconsin_CS27_North = 14801 Proj_Wisconsin_CS27_Central = 14802 Proj_Wisconsin_CS27_South = 14803 Proj_Wisconsin_CS83_North = 14831 Proj_Wisconsin_CS83_Central = 14832 Proj_Wisconsin_CS83_South = 14833 Proj_Wyoming_CS27_East = 14901 Proj_Wyoming_CS27_East_Central = 14902 Proj_Wyoming_CS27_West_Central = 14903 Proj_Wyoming_CS27_West = 14904 Proj_Wyoming_CS83_East = 14931 Proj_Wyoming_CS83_East_Central = 14932 Proj_Wyoming_CS83_West_Central = 14933 Proj_Wyoming_CS83_West = 14934 Proj_Alaska_CS27_1 = 15001 Proj_Alaska_CS27_2 = 15002 Proj_Alaska_CS27_3 = 15003 Proj_Alaska_CS27_4 = 15004 Proj_Alaska_CS27_5 = 15005 Proj_Alaska_CS27_6 = 15006 Proj_Alaska_CS27_7 = 15007 Proj_Alaska_CS27_8 = 15008 Proj_Alaska_CS27_9 = 15009 Proj_Alaska_CS27_10 = 15010 Proj_Alaska_CS83_1 = 15031 Proj_Alaska_CS83_2 = 15032 Proj_Alaska_CS83_3 = 15033 Proj_Alaska_CS83_4 = 15034 Proj_Alaska_CS83_5 = 15035 Proj_Alaska_CS83_6 = 15036 Proj_Alaska_CS83_7 = 15037 Proj_Alaska_CS83_8 = 15038 Proj_Alaska_CS83_9 = 15039 Proj_Alaska_CS83_10 = 15040 Proj_Hawaii_CS27_1 = 15101 Proj_Hawaii_CS27_2 = 15102 Proj_Hawaii_CS27_3 = 15103 Proj_Hawaii_CS27_4 = 15104 Proj_Hawaii_CS27_5 = 15105 Proj_Hawaii_CS83_1 = 15131 Proj_Hawaii_CS83_2 = 15132 Proj_Hawaii_CS83_3 = 15133 Proj_Hawaii_CS83_4 = 15134 Proj_Hawaii_CS83_5 = 15135 Proj_Puerto_Rico_CS27 = 15201 Proj_St_Croix = 15202 Proj_Puerto_Rico_Virgin_Is = 15230 Proj_BLM_14N_feet = 15914 Proj_BLM_15N_feet = 15915 Proj_BLM_16N_feet = 15916 Proj_BLM_17N_feet = 15917 Proj_Map_Grid_of_Australia_48 = 17348 Proj_Map_Grid_of_Australia_49 = 17349 Proj_Map_Grid_of_Australia_50 = 17350 Proj_Map_Grid_of_Australia_51 = 17351 Proj_Map_Grid_of_Australia_52 = 17352 Proj_Map_Grid_of_Australia_53 = 17353 Proj_Map_Grid_of_Australia_54 = 17354 Proj_Map_Grid_of_Australia_55 = 17355 Proj_Map_Grid_of_Australia_56 = 17356 Proj_Map_Grid_of_Australia_57 = 17357 Proj_Map_Grid_of_Australia_58 = 17358 Proj_Australian_Map_Grid_48 = 17448 Proj_Australian_Map_Grid_49 = 17449 Proj_Australian_Map_Grid_50 = 17450 Proj_Australian_Map_Grid_51 = 17451 Proj_Australian_Map_Grid_52 = 17452 Proj_Australian_Map_Grid_53 = 17453 Proj_Australian_Map_Grid_54 = 17454 Proj_Australian_Map_Grid_55 = 17455 Proj_Australian_Map_Grid_56 = 17456 Proj_Australian_Map_Grid_57 = 17457 Proj_Australian_Map_Grid_58 = 17458 Proj_Argentina_1 = 18031 Proj_Argentina_2 = 18032 Proj_Argentina_3 = 18033 Proj_Argentina_4 = 18034 Proj_Argentina_5 = 18035 Proj_Argentina_6 = 18036 Proj_Argentina_7 = 18037 Proj_Colombia_3W = 18051 Proj_Colombia_Bogota = 18052 Proj_Colombia_3E = 18053 Proj_Colombia_6E = 18054 Proj_Egypt_Red_Belt = 18072 Proj_Egypt_Purple_Belt = 18073 Proj_Extended_Purple_Belt = 18074 Proj_New_Zealand_North_Island_Nat_Grid = 18141 Proj_New_Zealand_South_Island_Nat_Grid = 18142 Proj_Bahrain_Grid = 19900 Proj_Netherlands_E_Indies_Equatorial = 19905 Proj_RSO_Borneo = 19912 +----------------------------------+ 6.3.3.3 Coordinate Transformation Codes Ranges: 0 = undefined [ 1, 16383] = GeoTIFF Coordinate Transformation codes [16384, 32766] = Reserved by GeoTIFF 32767 = user-defined [32768, 65535] = Private User Implementations Values: CT_TransverseMercator = 1 CT_TransvMercator_Modified_Alaska = 2 CT_ObliqueMercator = 3 CT_ObliqueMercator_Laborde = 4 CT_ObliqueMercator_Rosenmund = 5 CT_ObliqueMercator_Spherical = 6 CT_Mercator = 7 CT_LambertConfConic = 8 CT_LambertConfConic_Helmert = 9 CT_LambertAzimEqualArea = 10 CT_AlbersEqualArea = 11 CT_AzimuthalEquidistant = 12 CT_EquidistantConic = 13 CT_Stereographic = 14 CT_PolarStereographic = 15 CT_ObliqueStereographic = 16 CT_Equirectangular = 17 CT_CassiniSoldner = 18 CT_Gnomonic = 19 CT_MillerCylindrical = 20 CT_Orthographic = 21 CT_Polyconic = 22 CT_Robinson = 23 CT_Sinusoidal = 24 CT_VanDerGrinten = 25 CT_NewZealandMapGrid = 26 CT_SouthOrientedGaussConformal = 27 Aliases: CT_AlaskaConformal = CT_TransvMercator_Modified_Alaska CT_TransvEquidistCylindrical = CT_CassiniSoldner CT_ObliqueMercator_Hotine = CT_ObliqueMercator CT_SwissObliqueCylindrical = CT_ObliqueMercator_Rosenmund CT_GaussBoaga = CT_TransverseMercator CT_GaussKruger = CT_TransverseMercator +----------------------------------+ 6.3.4 Vertical CS Codes +----------------------------------+ 6.3.4.1 Vertical CS Type Codes Ranges: 0 = undefined [ 1, 4999] = Reserved [ 5000, 5099] = EPSG Ellipsoid Vertical CS Codes [ 5100, 5199] = EPSG Orthometric Vertical CS Codes [ 5200, 5999] = Reserved EPSG [ 6000, 32766] = Reserved 32767 = user-defined [32768, 65535] = Private User Implementations Values: VertCS_Airy_1830_ellipsoid = 5001 VertCS_Airy_Modified_1849_ellipsoid = 5002 VertCS_ANS_ellipsoid = 5003 VertCS_Bessel_1841_ellipsoid = 5004 VertCS_Bessel_Modified_ellipsoid = 5005 VertCS_Bessel_Namibia_ellipsoid = 5006 VertCS_Clarke_1858_ellipsoid = 5007 VertCS_Clarke_1866_ellipsoid = 5008 VertCS_Clarke_1880_Benoit_ellipsoid = 5010 VertCS_Clarke_1880_IGN_ellipsoid = 5011 VertCS_Clarke_1880_RGS_ellipsoid = 5012 VertCS_Clarke_1880_Arc_ellipsoid = 5013 VertCS_Clarke_1880_SGA_1922_ellipsoid = 5014 VertCS_Everest_1830_1937_Adjustment_ellipsoid = 5015 VertCS_Everest_1830_1967_Definition_ellipsoid = 5016 VertCS_Everest_1830_1975_Definition_ellipsoid = 5017 VertCS_Everest_1830_Modified_ellipsoid = 5018 VertCS_GRS_1980_ellipsoid = 5019 VertCS_Helmert_1906_ellipsoid = 5020 VertCS_INS_ellipsoid = 5021 VertCS_International_1924_ellipsoid = 5022 VertCS_International_1967_ellipsoid = 5023 VertCS_Krassowsky_1940_ellipsoid = 5024 VertCS_NWL_9D_ellipsoid = 5025 VertCS_NWL_10D_ellipsoid = 5026 VertCS_Plessis_1817_ellipsoid = 5027 VertCS_Struve_1860_ellipsoid = 5028 VertCS_War_Office_ellipsoid = 5029 VertCS_WGS_84_ellipsoid = 5030 VertCS_GEM_10C_ellipsoid = 5031 VertCS_OSU86F_ellipsoid = 5032 VertCS_OSU91A_ellipsoid = 5033 Orthometric Vertical CS; VertCS_Newlyn = 5101 VertCS_North_American_Vertical_Datum_1929 = 5102 VertCS_North_American_Vertical_Datum_1988 = 5103 VertCS_Yellow_Sea_1956 = 5104 VertCS_Baltic_Sea = 5105 VertCS_Caspian_Sea = 5106 +----------------------------------+ 6.3.4.2 Vertical CS Datum Codes Ranges: 0 = undefined [ 1, 16383] = Vertical Datum Codes [16384, 32766] = Reserved 32767 = user-defined [32768, 65535] = Private User Implementations No vertical datum codes are currently defined, other than those implied by the corrsponding Vertical CS code. +--------------------------------------------------------------------+ +----------------------------------------------------------------------+ 7. Glossary +--------------------------------------------------------------------+ ASCII - [American Standard Code for Information Interchange] The predominant character set encoding of present-day computers. Cell - A rectangular area in Raster space, in which a single pixel value is filled. Code - In GeoTIFF, a code is a value assigned to a GeoKey, and has one of 65536 possible values. Coordinate System - A systematic way of assigning real (x,y,z..) coordinates to a surface or volume. In Geodetics the surface is an ellipsoid used to model the earth. Datum - A mathematical approximation to all or part of the earth's surface. Defining a datum requires the definition of an ellipsoid, its location and orientation, as well as the area for which the datum is valid. Device Space - A coordinate space referencing scanner, printers and display devices. DOUBLE - 8-bit IEEE double precision floating point. Ellipsoid: A mathematically defined quadratic surface used to model the earth. Flattening - For an ellipsoid with major and minor axis lengths (a,b), the flattening is defined by: f = (a - b)/a For the earth, the value of f is approximately 1/298.3 Geocoding - An image is geocoded if a precise algorithm for determining the earth-location of each point in the image is defined. Geographic Coordinate System - A Geographic CS consists of a well-defined ellipsoidal datum, a Prime Meridian, and an angular unit, allowing the assignment of a Latitude-Longitude (and optionally, geodetic height) vector to a location on earth. GeoKey - In GeoTIFF, a GeoKey is equivalent in function to a TIFF tag, but uses a different storage mechanism. Georeferencing - An image is georeferenced if the location of its pixels in some model space is defined, but the transformation tying model space to the earth is not known. GeoTIFF - A standard for storing georeference and geocoding information in a TIFF 6.0 compliant raster file. Grid - A coordinate mesh upon which pixels are placed IEEE Institute of Electrical and Electronics Engineers, Inc. IFD - In TIFF format, an Image File Directory, containing all the TIFF tags for one image in the file (there may be more than one). Meridian - Arc of constant longitude, passing through the poles. Model Space - A flat geometrical space used to model a portion of the earth. Parallel - Lines of constant latitude, parallel to the equator. Pixel - A dimensionless point-measurement, stored in a raster file. Prime Meridian - An arbitrarily chosen meridian, used as reference for all others, and defined as 0 degrees longitude. Projection - A projection in GeoTIFF consists of a linear (X,Y) coordinate system, and a coordinate transformation method (such as Transverse Mercator) to tie this system to an unspecified Geographic CS.. Projected Coordinate System - A PCS consists of a Geographic (Lat-Long) coordinate system, and a Projection to tie this system to a linear (X,Y) space. Raster Space - A continuous planar space in which pixel values are visually realized. RATIONAL - In TIFF format, a RATIONAL value is a fractional value represented by the ratio of two unsigned 4-byte integers. SDTS - The USGS Spatial Data Transmission Standard. Tag - In TIFF format, a tag is packet of numerical or ASCII values, which have a numerical "Tag" ID indicating their information content. TIFF - Acronym for Tagged Image File Format; a platform-independent, extensive specification for storing raster data and ancillary information in a single file. USGS - U.S. Geological Survey +---------------------------------------------------------------------+, END OF SPECIFICATION +---------------------------------------------------------------------+