Why is GeoTIFF based only on TIFF format?
… instead of, say, GIF or BMP or LAN or IMG or other formats? TIFF is already used for geographic imagery, using certain proprietary tag structures. GeoTIFF merely expands this to involve public domain tags and structures that are interoperable between any GIS. TIFF is the only format in the public domain which can support the wide variety of image types already used for geographic imagery. TIFF can support 8-bit black and white images, up to 16 and 32 bit elevation models, 24 bit color imagery, and any other type of image. TIFF also supports the most varieties of compression and tiling options, to increase the efficiency of image transfer and utilization. The other data formats possible are limited in these areas, or are still merely proposals, while TIFF has been implemented for a decade or so. It is almost the only format which allows the flexibility to support tag structures, like the geographic metadata of GEOTIFF, without causing a conflict with non-geographic uses of the raste
