CompuServe Messages

I bought the CD-ROM disk in either '87 or '88 from the U.S. Geological Service. It contained (So they told me, remember I never had a machine to actually read the disk) the digital line graphs (DLG) at 1:250,000 for the U.S. (might have been 1:100,000 ???). I subsequently managed to get 5 or 6 DLG files in an IBM disk format and by lots of grief transferred them to the Amiga. I wrote a little Lattice C program to read and display the files using a superbitmap program from C. Schwepper (sp?) at CIS. At that point, I could tell you where every railroad track in Rockford,Ill was located. With another file I could plot the highways, etc. The file format was very accurately described in USGS brochures. Since then, the DLG files have been replaced by TIGER files, which were organized for the 1990 census. It may be difficult to get the 1987 DLG files on CD-ROM (or there may still be lots of them, I don't really know). A magazine called CD-ROM used to publish an annual list of retail CD-ROM disks. That list included the USGS disk and maybe a dozen other government disks that sold for under $50.00. It also listed many, many disks by private companies (usually for well over $200) Let me know if you need more information on the USGS CD-ROM stuff. I haven't looked at it in well over a year, but it should be around here somewhere.