Dear all,
I like to maintenance datas in OSM first time.
Therefore I walked along a footpath with my gps devices and load the related
gps track into josm.
It looks like the footpath lead through the periphery of houses etc.
To say it short, I’m not sure if it would be ok to upload the footpath to OSM to avoid bad or wrong data.
Perhaps you like to help me a little bit ?
Buy the way, how do you prevent the map from bad data ?
Kind Regards
Rawbit
The GPS track is likely to be 10s of metres off the true position, so you should use it as just one input.
As there is now some aerial imagery that is licensed for OSM use, generally you will use the GPS track as a guide to finding track on imagery, and to interpolate sections where vegetation or shadows obscure it.
The imagery will itself not be completely accurate, and different versions of nominally the same image may have different offsets. Especially were a feature is not directly below the camera, and there are height differences, there may be parallax errors.
You have to take all the sources into account. In some cases there may be enough evidence to justify moving an existing feature, but normally you will have to adjust new features to get the correct topological relationship with existing features.
Also note that you should normally smooth out GPX tracks. Most of the fine detail will be measurement noise, not the real course of the track.
If you are not sure which side of a house the track passed, you should add a fixme tag.
Hello Rawbit,
maybe you can find some tools in the OSm wiki about http://wiki.openstreetmap.org/wiki/Edit_GPS_tracks
There you can have different backgrounds wheer you can check the accuracy of your recorded track.
But be aware: aerial images like BING or Mapbox satellite can have an offset relative to real world, too.