On Tue, December 13, 2011 23:17, Jo wrote: > I'm also taking the opportunity to align all the other features on bing.
Have you checked the local alignment of Bing aerials? Where I am they can be offset by as much as 20 metres! I have to realign the aerial photo layer before tracing anything from Bing. The same problem was present in Yahoo! aerials, but the offsets were different. Generally what I do is make several GPS traces around a very visible object (such as a field, running track, monument or something) then I average the traces to get a good outline. Once I have the outline accurately recorded in OSM I adjust the position of the aerial photos until the physical object lines up with the OSM outline. Then I can map other things nearby. I have found that a single adjustment can apply to areas 40 km away, sometimes more, sometimes less. Other people's GPS traces are good for double checking the alignment further away. Once I have a good alignment I record it in JOSM so I can re-use it again later. Best wishes, Andrew _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk
