Editing GeoTIFF

{{Incomplete|2=description of how metadata is included|date=May 2024|article}}{{Short description|Georefence standard for TIFF file format}}

'''GeoTIFF''' is a [[public domain]] [[Metadata (computing)|metadata]] standard which allows [[Georeference|georeferencing]] information to be embedded within a [[TIFF]] file. The potential additional information includes [[map projection]], [[coordinate system]]s, [[ellipsoid]]s, [[datum (geodesy)|datum]]s, and everything else necessary to establish the exact spatial reference for the file.  The GeoTIFF format is fully compliant with TIFF 6.0, so software incapable of reading and interpreting the specialized metadata will still be able to open a GeoTIFF format file.<ref>Sk. Sazid Mahammad, R. Ramakrishnan, [https://www.geospatialworld.net/article/geotiff-a-standard-image-file-format-for-gis-applications/ GeoTIFF - A standard image file format for GIS applications]. Retrieved on 2017-02-01.</ref>

An alternative to the "inlined" TIFF geospatial metadata is the [[World file|*.tfw World File]] [[sidecar file]] format which may sit in the same folder as the regular TIFF file to provide a subset of the functionality of the standard GeoTIFF described here.

== History ==
The GeoTIFF format was originally created by Dr. Niles Ritter while he was working at the [[NASA]] [[Jet Propulsion Laboratory]].<ref>Ruth, Mike (February 2005).  [http://www.remotesensing.org/geotiff/faq.html#Who%20owns%20GeoTIFF%20Format? Who owns the GeoTIFF format?] {{webarchive|url=https://web.archive.org/web/20141019224933/http://www.remotesensing.org/geotiff/faq.html |date=2014-10-19 }}. Retrieved on 2008-02-16.</ref> The [[reference implementation]] code was released mostly as [[public domain software]] with some parts under a [[Permissive license|permissive]] [[X license]].<ref>[ftp://ftp.remotesensing.org/geotiff/liopebgeotiff/libgeotiff125.zip libgeotiff125.zip]{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}} on remotesensing.org in license ''"libgeotiff Licensing - All the source code in this toolkit are either in the public domain, or under an X style license.  In any event it is all considered to be free to use for any purpose (including commercial software).  No credit is required though some of the code requires that the specific source code modules retain their existing copyright statements.  The CSV files, and other tables derived from the EPSG coordinate system database are also free to use.  In particular, no part of this code is "copyleft", nor does it imply any requirement for users to disclose this or their own source code. All components not carrying their own copyright message, but distributed with libgeotiff should be considered to be under the same license as Niles' code."''</ref> On September 14, 2019, the [[Open Geospatial Consortium]] (OGC) published the OGC GeoTIFF standard,<ref>Open Geospatial Consortium, [https://www.opengeospatial.org/standards/geotiff OGC GeoTIFF Standard]. Retrieved on 2019-11-07.</ref> which defines the Geographic Tag Image File Format (GeoTIFF) by specifying requirements and encoding rules for using the Tag Image File Format (TIFF) for the exchange of georeferenced or geocoded imagery. The OGC GeoTIFF 1.1 standard formalizes the existing community GeoTIFF specification version 1.0 and aligns it with the continuing addition of data to the [[EPSG]] Geodetic Parameter Dataset.

== Cloud Optimized GeoTIFF ==

"Cloud Optimized GeoTIFF" (COG) is a standard based on GeoTIFF, designed to make it straightforward to use GeoTIFFs hosted on [[HTTP]] webservers, so that users and software can make use of partial data within the file without having to download the entire file.<ref name=cogeo>{{Cite web|url=https://www.cogeo.org/|title=Cloud Optimized GeoTIFF|website=www.cogeo.org}}</ref><ref name=cogeospec>{{Cite web|url=https://github.com/cogeotiff/cog-spec/blob/203241975d054e5c933493f65bc4810e93d0048a/spec.md|title=cog-spec|date=January 20, 2023|via=GitHub}}</ref> It is designed to work with HTTP range requests, and specifies a particular layout of data and metadata within the GeoTIFF, such that clients can predict which range of bytes they need to download. COG is simply a specialisation of GeoTIFF, so COG files are TIFF files.

The pattern of optimizing GeoTIFFs for HTTP range requests was first demonstrated at large scale when [[AWS]] started hosting [[Landsat]] data on [[Amazon S3]] in 2015.<ref>[https://dusk.geo.orst.edu/Pickup/Esri/AGU2015/IN43B-1727-AWS.pdf Sundwall, Jed. "Landsat on Amazon Web Services". American Geophysical Union, San Francisco, 2015.]</ref> The pattern was developed into the COG within the [[Open Source Geospatial Foundation]]/[[GDAL]] project, starting in around 2016.<ref>{{Cite web|url=https://trac.osgeo.org/gdal/wiki/CloudOptimizedGeoTIFF|title=CloudOptimizedGeoTIFF – GDAL|website=trac.osgeo.org}}</ref> The COG format can be read and written by many common geographic software tools including [[GDAL]], [[QGIS]], and [[GeoTrellis]].<ref name=holmes2018>{{Cite web|url=https://medium.com/radiant-earth-insights/cloud-optimized-geotiff-advances-6b01750eb5ac|title=Cloud Optimized GeoTIFF Advances|first=Chris|last=Holmes|date=June 5, 2018}}</ref> Various providers now supply some of their data in COG format, including [[USGS]],<ref>{{Cite web|url=https://www.usgs.gov/landsat-missions/landsat-collection-2|title=Landsat Collection 2 &#124; U.S. Geological Survey|website=www.usgs.gov}}</ref> [[NASA]],<ref>{{Cite web|url=http://www.earthdata.nasa.gov/engage/cloud-optimized-geotiffs|title=NASA Datasets Available in Cloud Optimized GeoTIFFs|first=NASA|last=Earth Science Data Systems|date=May 28, 2020|website=Earthdata}}</ref> [[Google]]<ref name=holmes2018 /> and [[DigitalGlobe]].<ref>{{Cite web|url=https://blog.maxar.com/earth-intelligence/2018/cloud-optimized-geotiffs-and-the-path-to-accessible-satellite-imagery-analytics|title=Cloud optimized GeoTIFFs and the path to accessible satellite imagery…|website=Maxar Blog}}</ref>

== See also ==
* [[Digital raster graphic]]
* [[GDAL]] - Open source GeoTIFF reader and writer
* [[Tag Image File Format|Tag Image File Format (TIFF)]]
* [[World file|The *.tfw World File]]

== References ==
{{reflist|30em}}

==Further reading==
* {{cite web | title=The Secret Life of GeoTIFFs | website=The Library of Congress | date=2023-05-18 | url=https://blogs.loc.gov/maps/2023/05/the-secret-life-of-geotiffs/ | ref={{sfnref|The Library of Congress|2023}} | access-date=2025-03-08}}
* {{cite web |url= http://www.geospatialworld.net/article/geotiff-a-standard-image-file-format-for-gis-applications/ |title= GeoTIFF - A standard image file format for GIS applications |publisher= Geospatial World |date= Sep 1, 2009 |quote= Details backwards compatible GeoTIFF extensions to the TIFF file format and header }}

==External links==
* [https://www.opengeospatial.org/standards/geotiff OGC GeoTIFF] formalizes the existing community GeoTIFF specification version 1.0 and aligns it with the continuing addition of data to the EPSG Geodetic Parameter Dataset.
* [https://geotiff.io GeoTIFF.io] Open-source website for viewing and analyzing GeoTIFF files
* {{official website}}

[[Category:GIS raster file formats]]
[[Category:Public-domain software with source code]]