Zip Code Radius Finder and Calculator. Zipdecode. Hit the letter z, or click the word zoom to enable or disable zooming. zipdecode This project began a very short sketch (a few hours) that I created in 1999 because curious about how the numbering works for postal codes in the states.
A detailed description of this project (and source code built with Processing) can be found in my book Visualizing Data. Updated September 2004 to add several features over the original, including zoom, some new colors (thanks to Eugene Kuo), and a better zip code database (because of all the people who emailed and were sad that they couldn't find themselves). Free ZIP Code to MSA and MSA to ZIP Code information. Click for a zip code picture.