This is really outside the scope of maemo-mapper, but I'd be interested in what people think. Maemo-mapper, GPS and Google Earth are now so good that we can see errors in some of the data available. In Trinidad, I can consistently see a 15m offset between GPS locations and Google Earth/Maps data. For instance, the attached file shows a track I drove this morning plotted on Google Earth (I see the same offset on the n800 when I use Google Maps). There was very good visibility of satellites, so the error in the location should be less than 5 metres.