[OSM-talk] Retaggin of ways
Tom Hughes
tom at compton.nu
Thu Dec 6 08:37:28 GMT 2007
In message <1196890008.22494.33.camel at localhost.localdomain>
Jon Burgess <jburgess777 at googlemail.com> wrote:
> You need to be careful about the relative accuracy of different sources.
> I believe that GPS traces are generally more accurate for road positions
> than Yahoo! imagery (especially if there are several GPS traces covering
> the same road).
>
> Adding roads based on Y! when there are no other traces is fine but
> please don't re-align existing roads just to fit the Y! images.
I do it all the time as it generally gives a much better idea of the
true shape and position of the road then the GPX trace which will
often be (a) off to one side if you were walking/cycling or (b) will
tend to smooth out the curves just because you will shortcut them
when possible when driving/cycling.
I do have the advantage of having lots of evidence (from comparing
traces with imagery) that the imagery round me is well positioned
though, and obviously if I had reason to believe it wasn't then it
would be a different story.
Tom
--
Tom Hughes (tom at compton.nu)
http://www.compton.nu/
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