Where do the country codes come from?
I have added the country codes to the place names, they are taken from the codes given to the web domains of the countries, e.g. DE for Germany. For the US states I used the 2 letter postal codes, e.g. CA for California. Can you say more about the inner workings of the program? The cgi program written in C gets called with a request to print one sub tile: /cgi-bin/gtopo30?TPL=pwrl/tilegtop&LAT=480000N&LON=0120000E The program reads a 41 by 41 elevation point square with the given location at the upper left corner from the GTOPO30 data. The number 41 is a value that I defined, it leads to a sub tile with 1600 vertexes. 9 of those subtiles are displayed at any given time, my computer can handle the 15000 vertex VRML model resulting but not much more :-). With 30 arc second grid spacing of GTOPO30 the nine subtiles together exactly display one square degree. Next the program assigns the color values to the points. Hilltops, slopes and valleys get different color values, the color depends
