Lucene 4.X is a great tool for analyzing cellphone location data (Did you really think only the NSA has it?).
Chilamakuru Vishnu gets us started with a code heavy post with the promise of:
My Next Blog Post will talk about how to implement advanced spatial queries like
geoInterseting – where one polygon intersects with another polygon/line.
geoWithIn – where one polygon lies completely within another polygon.
Or you could obtain geolocation data by other means.
I first saw this at DZone.