This document analyzes social communities based on location data from a location-based social networking website called Gowalla. It obtains user location records from Austin, TX between April and July 2010. It creates encounter graphs and uses the Louvain method to determine communities for each month. It analyzes the evolution of communities over time by matching communities between months. Contour maps are used to visualize community locality and movement patterns. The study examines similarities and differences between human social communities and vehicular encounter patterns.