[josm-dev] Editing Antarctica

[Jochen Topf]

Hi!

I am currently working with Christoph Hormann on improving the data for
Antarctica. See http://wiki.openstreetmap.org/wiki/Antarctica for more
info.

One problem is that Antarctica doesn't work well in EPSG:4326 plate carree
projection. (Mercator is right out because it stops at about 85° South.)

Yes, we can edit the data in JOSM, but the nearer you get to the pole the more
distortions you get. This is problematic when editing buildings for instance,
because they are not rectangular in JOSM. But this is also a problem when
deriving data from satellite images. There are WMS services with satellite
images that we could use that allow EPSG:3031 polar stereographic projection.
But JOSM doesn't support that projection.

The problem with using 4326 is that when digitising from an image you will
probably not use the right detail. Normally you would space out the nodes
along some feature evenly, but with so much distortion you can't see what
an even distribution would be. The result is that the features would look
ragged in some map projections.

How difficult would it be to support EPSG:3031 in JOSM?

Jochen
-- 
Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298