Gervase Markham wrote: > Richard Fairhurst wrote: > >> To answer the original question, though, trust your GPS over the >> imagery. The imagery may not always be rectified, whereas as long as >> your GPS has produced a good-quality track - i.e. no "concrete >> canyon" distortions - it should always be accurate. >> > > OK. So if that's the answer (and it's sort of what I expected) then the > follow-up question is: do we have any procedure for fixing the > rectification, or letting Yahoo know their images are out? > I don't think that there's an option to do this in the flash editor; potlatch. However, if you're feeling brave then the java editor JOSM will allow the layers to be moved. You will need the wms and the ywms plugins.
My experience is that when the signal strength is good, then my tracks will be spot on and agree exactly with the yahoo mapping. The GPS usually keeps track of a the accuracy in a parameter called hdop, you may be able to see this if you look at the gpx tracklog. Values less than 10 should be okay, if it's below 4 then there is a good chance you can rely on it. If we view GPS tracks as being accurate to 10m anyway so if the difference is small then I would fret too much. In my view it's more important that the relative positions are correct rather than everything being absolutely correct. OSM works on a refinement policy enter the data to the best of your knowledge at the time and either your self or someone else can improve it in the future. Cheers Chris -- http://www.chrisfleming.org/ _______________________________________________ newbies mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/newbies
