sailplay parses NMEA0183 data from a GPS data logger, and replays the sailboarder, kite surfer, cyclist, motorcyclist, etc. being logged on a 3D moving map. The end result is a Y4M video file that is ready to be converted to a movie file (MPEG, AVI etc). Optionally, the user can take screenshots. This program can display/record multiple participants (i.e. display/record more than one GPS file).