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Is the satilite Maps the best thing to match roads with?

Posted: Wed Oct 14, 2009 4:24 pm
by mobile_bob
I have been using the satellite maps to correct roads, because my GPS records (From the Iphone) are pretty inaccurate. Is this the best policy? Should the roads follow the satellite map or is that just a visual suggestion and not very accurate either?

Travis

Re: Is the satilite Maps the best thing to match roads with?

Posted: Wed Oct 14, 2009 4:43 pm
by RallyChris
I find that the background overlay is fine for adding things if there are just not enough GPS tracks to average out. Note that in some areas the background is actual aerial photography, so depending on the angle the photo was taken at the roads might not match up well.

As long as it is in the ballpark, Waze will move it around with enough route data during the nightly data crunching.

Re: Is the satilite Maps the best thing to match roads with?

Posted: Wed Oct 14, 2009 4:58 pm
by sketch
Ultimately, using the average of your GPS traces will be the best thing to do, although you'll need to drive a road at least a dozen times for them to average out enough to eliminate outliers. I would match them to the satellite map for now and use the GPS data to line it up later, if you're getting big tracking problems.

I've noticed a bunch of straight bridges aren't straight in the satellite pictures. I guess the angle of the satellite photo caused them to look curved! In this case it seems that I'm lucky to live in a city with about a 10 foot range of elevations :lol: