[Talk-GB] New Bing Imagery

Russ Garrett russ at garrett.co.uk
Wed Aug 19 15:21:00 UTC 2020


On Wed, 19 Aug 2020 at 16:00, Colin Smale <colin.smale at xs4all.nl> wrote:
> At least it sounds soluble. Given the right transform and corrections a "definitive" OS point in Easting/Northing format can be translated accurately to WGS84 lat/long. However you look at it, I would expect a purely mathematical transformation should have less error than a transformation involving "tracing" from imagery whose rectification has probably also involved some of these transformations each with their own error terms. But I suppose that it at least partly depends on your definition of "perfection."

Well, that assumes that OS's locations are perfect, and that their
data isn't subject to orthorectification errors and the like. It's
still likely to be better than any other source, but I'd be surprised
if there weren't similar errors in some of the OS data, especially in
more rural & hilly areas.

In my experience, once you start trying to go below 5m accuracy you
swiftly learn not to trust anyone.

Cheers,

-- 
Russ Garrett
russ at garrett.co.uk



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