I have used the gmap-pedometer app for years to measure running routes. It's good, but can be off after several miles if you don't track turns properly. Then I wondered how accurate it would be on a specific short distance. So I tried it on a town pool (Colonie NY) which states it is Olympic Size. I have always logged laps there in meters, but you never really know when they say that, whether it's yards or meters. Here's a link to the map which showed me exactly 50 meters.
www.gmap-pedometer.com/
