On Wed, Apr 7, 2010 at 12:42, Richard Fairhurst <[email protected]>wrote:
> Chris Browet wrote: > > I'm not too sure the reprojection from EPSG:27700 (OSGB36) to > > EPSG:900913 (Google) went perfect. > > If you're tracing from _any_ source without first aligning it with a > trustworthy ground reference (typically an average of existing GPS > tracks), You're Doing It Wrong. > Ok, but let's be practical. Same goes for every GPS traces used to create OSM. There should be many for the same road, then averaged, etc... I'm not sure there is a large percentage of OSM data meeting these criterias... Re tracing, you cannot deduce the projection (especially a tricky one like OSGB36) by aligning a number of points. If the base projection is wrong and a simple translation do not solve the problem, then you're roasted... Did you do the aligning exercise to check the validity of the OS Street View tiles (in EPSG:27700) and the reprojected ones (in EPSG:900913)? - Chris -
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