> oHw they [OSM] might've constructed their maps given the similarly noisy GPS samples Mark One Eyeball. OSM mappers manually convert the GPS traces to roads/

> oHw they [OSM] might've constructed their maps given the similarly noisy GPS samples Mark One Eyeball. OSM mappers manually convert the GPS traces to roads/features. You load the GPS trace into your editor, like a background layer. Then you draw in the road based on the GPS trace, and your common sense. But now-a-days aerial imagery is used a lot instead of GPS data.