[josm-dev] WMS layers default to "automatically change resolution"

[Stefan Breunig]

> The problem is that some servers we are using
> here might block you if you do too many requests in a short period of
> time,

The zoom snaps to certain resolutions to make caching work. Zooming out 
probably saves some requests because you need less tiles/images to fill 
your screen. Zooming in doesn’t, but then again I didn’t use high zoom 
levels very often in my practical tests. If you aren’t annoyed by this 
feature and only disable it out of fear to be rate-limited by your WMS, 
can you try it in every day use? Alternatively relay the WMS server 
details to me, so I can try. I believe having this default-on is more 
sensible, but only if it doesn’t turn out to be a problem.

> and there is only one actual resolution, which is equal or
> slightly above that of the original imagery and so makes sense to use
> if you want to get the maximum out of the imagery

I had a look at the WMS specification when implementing this and found 
nothing of relevance to get the “native resolution” or available 
pre-rendered ones.  I had a look at some WMS servers if there’s maybe a 
non-standard way of including this, but I didn’t find anything. Take 
the map4bw server, for example. It definitely has resolution 
information[1] but it’s not included in the WMS file[2].

Best regards,
Stefan

[1] http://www.webatlasde.de/ArcGIS/rest/services/Maps4BW/MapServer
[2] 
http://www.webatlasde.de/ArcGIS/services/Maps4BW/MapServer/WMSServer?request=GetCapabilities&service=WMS