On 14/06/2011 10:41, Craig Loftus wrote:
On 14 June 2011 10:26, Richard Fairhurst<rich...@systemed.net> wrote:
Potlatch 2's improved (not deployed yet) shapefile background layers asks
you for the projection before loading, rather than relying on the .prj file.
Thanks for clarifying.
I'm not very familiar with projections so a little more clarity would
be useful for me. As potlatch 'understands' OSGB, is loading an OSBG
shp file any more expensive than loading a WGS84 shp file?
If it is, it may be worthwhile reprojecting all the files. This would
also have the advantage of making the mirror useful for those of us
who simply refuse to stop using JOSM, despite all the awesome you keep
piling into potlatch.
Craig
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JOSM is perfectly capable of dealing with different projections: it's
how the French cadastre plugin works.
Adding an OSGB36 capability to JOSM would seem to the way to go.
There is a basic rule about shapefiles and OSM imports: learn about
projections first!
RichardF's mail shows why: if you dont add all the funny numbers at the
end of the projection (the Helmert Transform) things end-up 100m away
from where they should be! There's a good intro on the OS site, also
Chris Hill wrote a blog post about this last April or May.
Jerry
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