Implementing GeoKeys (GeoTIFF tags)

GeoTIFF files support standard TIFF comments and tags, but also contain six additional data tags describing the image location, scale, projection, and other information useful for topographic applications.

Three tags contain scalar data:

Three tags store additional values, called "GeoKeys":

There are 65536 possible GeoKeys.

The GeoTIFF spec recommends the following ranges (domains) for GeoTIFF data:

0..1023 Do not use; reserved for future use.
1024..2047 GeoTIFF Configuration keys.
2048..3071 Geographic/Geocentric CS Parameter keys.
3071..4095 Projected CS Parameter keys.
4096..5119 Vertical CS Parameter keys.
5120..32767 Reserved.
32768..65535 Private use -- use to store your own data.

Enumerate GeoKeys in an existing file by using EnumGeoKeys.

Read a specific GeoKey by using ReadGeoKey.

Use the GeoKeys property to prepare GeoKeys for file writing or saving. These GeoKeys are maintained as a per-thread array of GeoKeys.You can write the GeoKeys in two ways:

  1. When saving a new image as GeoTif , with one of the Save methods.
  2. You can update an existing file, using WriteGeoKeys.

Note: To save a region inside a TIFF file, you must have an unlocked Document or Medical Imaging license.

For more information on the GeoTIFF tags and for the complete list of the predefined GeoKeys values, refer to the GeoTIFF specifications found at

GeoTIFF files also support standard TIFF comments and tags. For more information on standard TIFF tags and comments, see Implementing TIFF Comments and Tags.

For technical reasons, the following restrictions apply when you pass an Image File Directory (IFD) offset by setting the CodecsTiffLoadOptions.ImageFileDirectoryOffset.htmlproperty if you set PageNumber to 1:

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