Open Street Map is a community built editable map that was featured at Where 2.0 2006 . They use user-contributed GPS traces as one of their data sources. At FOSS4G, I was just shown these great time-lapse animations of some data in London and Great Britian growing.
OSM is working with a London-based courier firm that provides GPS units to all of the their couriers. The couriers are on bicycles and motorized vehicles; all of their traces are uploaded once a week. The animation shows two days of their data. It’s fun to watch the flurry of courier activity throughout the day, watch it die down towards the evening, and then see the final burst of activity as all of the couriers head home from the pubs at the same time.
The other two videos show the build up of GPS traces for London and for Great Britian that were collected from May, 2005 to January, 2006. It’s amazing to see the blank slates slowly be filled in as Open Street Map’s user community has grown. This is especially visible in the GB video; the traces begin in London and then snake out to Brighton and Bristol. OSM has only increased in popularity since January, I hope that they create and release some updated videos. You can track their progress on their blog (also worth reading is Nick Black’s report on FOSS4G).