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Satellite Images versus GPS-Tracks

2

I went for a run with a Garmin Forerunner capturing the data for the entire route. I was on a paved trail for a lot of the run. I uploaded the gpx to OSM, and tried to add in a trail that was missing. However, the trail was clearly visible on the Bing satellite map, and it was a bit off from the gpx trail. Which should have precedence for plotting in OSM, the satellite image or the GPS data?

asked 12 May '11, 07:23

eallen's gravatar image

eallen
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accept rate: 0%

edited 12 May '11, 16:28

stephan75's gravatar image

stephan75
12.6k556210


One Answer:

3

As already answered in https://help.openstreetmap.org/questions/1200/which-is-more-reliable-gps-traces-or-aerial-imagery this is a hard question. Both aerial imagery and GPS tracks can be great or next to useless.

There are however a few things you can try:

See if your GPS tracks match the tracks by other mappers. If several GPS tracks taken over a few days are consistent with each outher then they are most likely correct and the aerial imagery is warped / shifted.

If there are not other tracks yet you can revisit the street the next day and take a second track. Again if it matches the first track it is most likely more accurate then the aerial imagery.

You can also check if different sources of aerial imagery are in agreement. If they are not at least one of the imagery layers in wrong.

If you don't fell certain enough to make the call after these test you should talk to other mappers in you area to find out what they use as authoritative source.

answered 12 May '11, 07:35

petschge's gravatar image

petschge
8.3k217398
accept rate: 21%

1

adding to petschge's answer before you use bing check, as he said that bing is aligned if not adjust it (space bar and drag) in case you didn't know

(12 May '11, 08:52) andy mackey

bing is air craft photography, i think

(12 May '11, 08:55) andy mackey

Source code available on GitHub .