Is GeoTIFF based on the world reference files that ESRI uses?
ESRI’s world file is a separate file with limited metadata content designed only for use in Arc/Info and other ESRI softwares, though widely supported by other software. The world reference file only contains the coefficients for an affine transformation between raster coordinates, and world coordinates, but no definition of the coordinate system. The GeoTIFF structure, by comparison, is rich in content and packs everything into a single file. The GeoTIFF tag stucture covers more diverse options for projection spaces, datums, ellipsoids, coordinate types, and related geographic features than the ESRI tag. And the GeoTIFF structure is intended to become entirely public domain, unlike tags withheld for private implementations.