Get a GPS module, and walk around a perimeter with Kismet running.
This is how Google Street view was essentially mapping WAPs on google maps, it's all publicly available and open software and you can pick up a USB GPS module for like $20 now.
"If art interprets our dreams, the computer executes them in the guise of programs!" - SICP
“If at first, the idea is not absurd, then there is no hope for it” - Albert Einstein