Thanks also to Sam Leffler and SGI for providing the marvelous Tiff library.
Jean-loup Gailly and Mark Adler are to be thanked for their zlib. Compression without the hassle, thanks guys.
Frank Warmerdam's work on libgeotiff and shapelib provided a groundwork for the support of those formats.
If you are serious about mapping, mapmaking, or GIS look for sites maintained by NOAA, USGS and USCG for lots of good information.