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.

I have noticed a similar, much larger, offset for Dominica using a handheld GPS: 150-200 metres. I posted to the Google Earth discussion forums, but never got a reply.

Data providers like Google do not seem to provide quantification of the accuracy of their data.

How could we improve the situation:

a) Feedback to the map providers
b) Create our own versions of map files, shifted as we see fit.
c) An option in maemo-mapper to shift map data by a user-specified amount.
d) Shut up and be happy with what we got.