|Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact|
|Full name||GeoTIFF, Revision 1.0|
GeoTIFF is format extension for storing georeference and geocoding information in a TIFF 6.0 compliant raster file by tying a raster image to a known model space or map projection. A GeoTIFF file is a TIFF 6.0 [TIFF_6] file, and inherits the file structure as described in the corresponding portion of the TIFF spec. The GeoTIFF format uses a defined set of TIFF tags to describe 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.
GeoTIFF can store a broad range of georeferencing information, catering to geographic as well as projected coordinate systems needs. Supported projections include UTM, US State Plane and National Grids, as well as the underlying projection types such as Transverse Mercator, Lambert Conformal Conic, etc. GeoTIFF uses a "MetaTag" (GeoKey) approach to encode dozens of information elements into just 6 private tags (33550, 34264, 33922, 34735, 34736, and 34737), taking advantage of TIFF platform-independent data format representation to avoid cross-platform interchange difficulties. GeoTIFF uses numerical codes to describe projection types, coordinate systems, datums, ellipsoids, etc. In the Format Specification Revision 1.0, see Section 2.4. GeoTIFF File and Key Structure and the Appendices for Tag ID, Key ID and numerical code details.
Like the TIFF format, GeoTIFF uses 32-bit offsets, limiting its extent to 4 gigabytes. The needs of GIS, large format scanners, medical imaging and other fields have prompted development of the variant BigTIFF format, which transcends the 4 GB TIFF limit using 64-bit offsets, thereby potentially supporting files up to 18,000 petabytes in size.
|Relationship to other formats|
|Subtype of||TIFF_6, TIFF, Revision 6.0|
|Has extension||BigTIFF, BigTIFF|
|Has later version||OGC GeoTIFF standard, version 1.1, not described separately at this website at this time.|
|Has subtype||Cloud Optimized GeoTIFF (COG), not described separately on this website. See https://www.cogeo.org/.|
|LC experience or existing holdings||The Library of Congress has acquired cartographic images in GeoTIFF format for its collections. An early example was the National Land Cover Dataset for 1992, acquired on CD. Where the Library once acquired ongoing map sets on paper, many are now acquired digitally. Such a map acquisition may include both a GeoTIFF created by scanning a paper map and vectorizations of the original as ESRI_shape or GeoDB_file format.|
|LC preference||The Library of Congress Recommended Formats Statement (RFS) includes GeoTIFF as a preferred format for GIS Raster and Georeferenced Images.|
|Disclosure||GeoTIFF is an open, fully documented extension to Aldus-Adobe's public domain Tagged-Image File Format (TIFF), Revision 6.0.|
|Documentation||Ritter, Niles and Mike Ruth, GeoTIFF Working Group. GeoTIFF Format Specification: GeoTIFF Revision 1.0, December 28, 2000. The "specification version" is given as 1.8.2.|
The development of the GeoTIFF 1.0 specification represented an effort by over 160 different remote sensing, GIS, cartographic, and surveying-related companies and organizations to establish a TIFF based interchange format for georeferenced raster imagery.
GeoTIFF has been widely supported for many years. In 2011, when the format was first described on this website, GIS/Image processing packages which supported GeoTIFF included: USGS's dlgv32, ESRI ArcInfo, ESRI ArcExplorer, ESRI ArcView, ERDAS IMAGINE, PCI’s EASI/PACE, MapInfo, Global Mapper, and Python Imaging Library.
The following examples of mainstream geospatial software applications supporting GeoTIFF are from early 2020, with links to lists of supported formats: ESRI ArcGIS and other ESRI products; ERDAS IMAGINE (now from Hexagon Geospatial); Global Mapper; MapInfo Professional (now from Pitney Bowes). Widely used software libraries supporting GeoTIFF include: libgeotiff; GDAL; and Safe Software FME.
USGS and other U.S. government agencies offer many imagery products in GeoTIFF format. Examples available in May 2020 include:
USGS has been closely involved with the development and promotion of the GeoTIFF format and tools to work with it. Global Mapper software, from Blue Marble Geographics, was developed in conjunction with USGS, and a limited-feature evaluation version of this software is available for download (also formerly known as USGS Digital Data Viewer: dlgv32 Pro). USGS provides a number of Raster Conversion Scripts that convert between GeoTIFF and other raster formats. An earlier standard employed by USGS, the Spatial Data Transfer Standard (SDTS), allowed a GeoTIFF image to be included in a transfer package with other files.
The U.S. DoD (Department of Defense) Information Technology Standards Registry (DISR) provides access to DoD/IC-approved GEO-Standards, including GeoTIFF 1.0. DoD has defined or endorsed profiles of GeoTIFF for particular application contexts. These include NGA.IP.0001 (NGA Implementation Profile for TIFF and GeoTIFF), a specification for the formatting of imagery and gridded data in TIFF format and OGC GML Application Schema-Coverage GeoTIFF Coverage Encoding Profile, v. 1.0, 2014-05-28, a profile of GMLCOV which specifies the usage of the GeoTIFF data format for the encoding of GML coverages.
Various lists of recommended formats for long-term archiving of scientific data include GeoTIFF as a recommended format: from NASA's ESDIS Standards Office (ESO): ESO Standards and Practices; from the University of Edinburgh Research Data Service, Choose the Best File Formats; from the U.S. National Archives, Format Guidance for the Transfer of Permanent Electronic Records: Geospatial Formats. See also Table 6.6 in Ecological Informatics: Data Management and Knowledge Discovery, Third Edition (2018).
|Licensing and patents||
Portions of the GeoTIFF 1.0 specification were copyrighted by Niles Ritter and Mike Ruth. Permission to copy without fee all or part of the specification material is granted provided that the copies are not made or distributed for direct or commercial advantage and the GeoTIFF specific copyright notice appears (see specification copyright notice). TIFF is a registered trademark of Aldus Corp., now owned by Adobe.
No concerns about patents in relation to GeoTIFF use of TIFF tags. No concerns about patents for underlying TIFF_6.
|Self-documentation||See TIFF_6. 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. See also Tags for TIFF and Related Specifications.|
|External dependencies||Requires a TIFF reader that is able to parse the Geokey MetaTag values (mentioned in Description), as well as to reliably execute two general requirements of the TIFF standard: to manage byte order (big and little endian) and to support for all documented TIFF 6.0 tag data-types, and in particular the IEEE double-precision floating point "DOUBLE" type tag.|
|Technical protection considerations|
|Normal rendering||Good support. 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. In systems that do not recognize the geographic tags, but do read TIFF image format, a GeoTIFF image should look and behave like any other TIFF image.|
|Clarity (high image resolution)||
Excellent support for images with very high spatial resolution. The standard is flexible as to color space and bit depth. In practice, 8-bit grayscale and 24-bit RGB color are common; some activities create files with greater than 8 bits per channel (color or grayscale).
|Color maintenance||See TIFF_6|
|GIS images and datasets|
The role of a GeoTIFF in normal GIS use is often as a visual base layer. The GeoTIFF format provides enough information that the software can automatically place an image without requirement of any user intervention, such as typing in coordinates, digitizing points, or other labor intensive and technical actions.
Most GeoTIFF-savvy systems look at the geographic information and use it without any requirement that the user know the content of the geographic tags. One aim of GeoTIFF is to reduce the need of users to be geographic experts in order to load a map-projected image or scanned map.
GeoTIFF provides a robust framework for specifying a broad class of existing projected coordinate systems.
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.
|Support for GIS metadata||GeoTIFF uses a small set of reserved TIFF tags to store a broad range of georeferencing information, including: coordinate systems, datums, ellipsoids, and projections.
Projections include UTM, US State Plane and National Grids, as well as the underlying projection types such as Transverse Mercator, Lambert Conformal Conic, etc.
The projection, datums and ellipsoid codes are derived from the EPSG list compiled by the Petrotechnical Open Software Corporation (POSC), and mechanisms for adding further international projections, datums and ellipsoids has been established.
|Support for grids||GeoTIFF images can be transformed and displayed as pixel based GRIDs.|
|Beyond normal functionality||
GeoTIFF is fully extensible, permitting internal, private or proprietary information storage.
As with TIFF, in GeoTIFF private "GeoKeys" and codes may be used, starting with 32768 and above. Unlike the TIFF spec, however, in GeoTIFF these private key-spaces will not be reserved, and are only to be used for private, internal purposes since the GeoTIFF standard arose from the need to avoid multiple proprietary encoding systems, use of private keycode implementations is discouraged.
|All sample file examples in official archive at http://download.osgeo.org/geotiff/samples/ have .tif as extension.|
|Internet Media Type||image/tiff
||See also TIFF_6|
|Wikidata Title ID||Q1502796
GeoTIFF projection, datums and ellipsoid codes are derived from the European Petroleum Survey Group (EPSG) list compiled by the Petrotechnical Open Software Corporation (POSC), and mechanisms for adding further international projections, datums and ellipsoids have 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).
The GeoTIFF specification requires that TIFF-compliant readers honor the 'byte-order' indicator: this means that 4-byte integers from files created on opposite order machines must be swapped in software, and that 8-byte DOUBLE's must be 8-byte swapped.
GeoTIFF requires reliable support for the TIFF 6.0 "DOUBLE" data-type tag, pertaining to IEEE double-precision floating point data. 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.
According to the specification of GeoTIFF 1.0 dated 2000, " 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."
For many years, the primary website for information about GeoTIFF, including the specification was at http://www.remotesensing.org/geotiff/geotiff.html. See first capture of the GeoTIFF Website by Internet Archive from May 3, 1999. By 2008, this URL redirected to http://geotiff.osgeo.org/, which redirected to http://trac.osgeo.org/geotiff/, hosted by the Open Source Geospatial Foundation (OSGeo). In late 2016, the use of the remotesensing.org domain as an entry point for the GeoTIFF specification and supporting documentation was terminated. Hosting continued to be provided by OSGeo. Starting in December 2018, https://trac.osgeo.org/geotiff/ indicated that the libgeoTIFF Github repository would be the primary location for maintenance and download of the libgeotiff software. [Note: As of May 2020, http://geotiff.osgeo.org/ redirected to the Github repository and https://trac.osgeo.org/geotiff/ was still actively maintained.]
In September 2019, OGC published version 1.1 of the GeoTIFF standard. Annex H: Backward compatibility states that revision 1.1 of GeoTIFF is aimed at being backward compatible with the 1.0 version both for coordinate reference systems based on EPSG register codes or user-defined coordinate reference systems. Names in the specification for GeoKeys have been updated for consistency with terminology for referencing by coordinates used by ISO TC211 (the ISO committee for standardization in the field of digital geographic information) and the OGC Abstract Specification Topic 2: Referencing by Coordinates. However, the numeric IDs for the keys, as used in GeoTIFF files, are retained.