How come my automobile track is frequently off by several hundred feet relative to the roads on my Garmin Oregon 400t Topo maps?
This is not a problem with GPS receiver accuracy, the issue is with the accuracy of road data in Garmin’s US Topo 2008 maps which come preinstalled on the Oregon. Many roads, especially secondary roads are off by 200′-500′ because of the inaccuracies in the data which Garmin used to build the maps. The location accuracy of geographic features in the preinstalled maps is more reliable.
