ewms plugin does not take JOSM projection setting into account

[jaak@…]

See longer description at ​http://wiki.openstreetmap.org/wiki/Talk:JOSM/Plugins/ewmsplugin#Other_projections

I see two technical issues here:

1. (any proper) WMS getMap request should include projection parameter, this is missing here. E.g. with Estonian Lambert should be "SRS=EPSG%3A3301", with default longitude-latitude should be SRS=EPSG:4326 etc
2. The request should be in same projection what is defined in JOSM properties. Currently it always sends longitude-latitude (expecting EPSG:4326).

There is one important special case: if JOSM uses Mercator, then some WMS servers actually accept also EPSG:4326 requests, and WMS server can do automatic simple affine transformation based on BBOX coordinates (actually just stretching in Y-axis), and the result happens to be nice and more or less correct, like converted to Mercator projection. I have found that MapServer does that, maybe some others also. Therefore the issue will not come out if you use Mercator projection. But with other (like Lambert) projections this basic conversion in WMS server side does not give good results, even if WMS server tries to do this, as these projections cannot be converted with basic affine transformation. Also if the server has e.g. aerial images then it can't accept EPSG:4326 to do explicit server-side reprojection.

[stoecker]

First step has been done. JOSM now knows the projection code of current projection.

[stoecker]

Fixed in WMS 13600.