GeoTIFFs

GeoTIFFs are raster image files that embed geographic information directly in the TIFF format. By including georeferencing metadata inside the file, GeoTIFFs enable GIS software to place an image in a real-world coordinate system without relying on separate world files. They are widely used for satellite imagery, aerial photos, digital elevation models, and scanned maps.

Georeferencing is encoded through TIFF tags and GeoTIFF tags. The ModelPixelScaleTag and ModelTiepointTag specify the affine transformation from pixel coordinates to map coordinates, and PixelIsArea or PixelIsPoint indicates pixel geometry. The GeoKeyDirectoryTag stores keys that identify the coordinate reference system, projection, datum, units, and related parameters, typically via EPSG codes.

GeoTIFFs support multiple data bands, various bit depths, and compression methods such as LZW, Deflate, or JPEG. The format remains compatible with major GIS tools and libraries, including GDAL, QGIS, ArcGIS, and ENVI. Because geographic information is embedded, sidecar world files are often unnecessary.

The GeoTIFF format originated in the 1990s through a collaboration of the GeoTIFF Working Group and is maintained by the GeoTIFF Committee. It defines how to store CRS metadata, datum, units, and projection parameters, and is widely adopted as a practical standard for georeferenced raster data.

Limitations and considerations: While robust, some software may interpret newer GeoKeys differently or require up-to-date CRS definitions. Users should verify coordinate system interpretation when exchanging GeoTIFFs and consider documenting any custom parameters to avoid misalignment when shared across platforms.