[OSM-talk] JOSM geometry support

Frederik Ramm frederik at remote.org
Thu Aug 23 23:46:28 BST 2007


Hi,

> In fact, the only way I can think of doing it properly would be to
> imagine the world as a sphere (now there's a thing)

Wo-hooo, not so fast ;-)

> However, does the projection issue really show up on something as
> small as roundabouts? 

Oh yes it does! See

http://www.remote.org/frederik/tmp/epsg4326.png
http://www.remote.org/frederik/tmp/mercator.png

- both show the same Karlsruhe roundabout, one with JOSM set to 
EPSG4236, one with JOSM set to Mercator. The "align in circle" will 
always create something that is a circle on screen, i.e. if I choose to 
work with EPSG4326 in JOSM and use "align nodes in circle", then a map 
created in the Mercator projection, e.g. our slippy maps, will show an 
oval that is much higher than it is wide.

As long as I leave JOSM set to Mercator it works fine, so it's not 
really a big issue.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'




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