The image above is a tiny portion of the huge Baltimore-Washington file. If you'd like to try something small, start with Manhattan or San Francisco . To use one of these ZIP files, download it and unzip it to create a file with a .llk extension. Compile and execute tgrmap.icn , passing the file name as a command-line parameter. You can use the mouse to sweep out an area of interest for zooming, and you can save a zoomed map or create a PostScript file for printing.
Further documentation is contained in the source code.
This mapping data was published by the Census Bureau in 1998. Unzip the county file, producing about 17 separate files. You may use tgrlink.icn to optimize the .lch file. The above sample files were all optimized in this way. By convention, we use the .llk extension for optimized .lch files.