[MapProxy] MapProxy - WMS feed from MapProxy renders tiles with different scale when compared with OSM on MapServer

Oliver Tonnhofer olt at omniscale.de
Mon Aug 25 23:39:53 PDT 2014


On 19.08.2014, at 19:00, andrew kovacs wrote:
> I am having some trouble figuring out why my cached images in MapProxy are a different scale than the source images on MapServer.  I have an OSM cache generated on MapServer and I can query this service directly from my client.  The WMS feed produces clear images which are the correct scale for my map extent.  However, when I request the WMS feed through MapProxy, the tiles that are generated (from the same source as the initial request) the scale appears to be off.  The images that are generated at the client level are not clear. 

You need to configure MapProxy to have a cache level with the same resolution that your client requests to get the best results. For example: If your client requests a 5m/px resolution but MapProxy has only cache levels for 4m/px and 8m/px, then it will take the 4m/px and resample that to the 5m/px resolution. You can change the resampling method to get better results, but it's still resampled.

You can add a debug source to your layer to see which resolution was requested by your client. But this will only work if your client makes requests at fixed scales. If that's not the case, then check out the res_factor and sqrt2 option.


Oliver Tonnhofer  | Omniscale GmbH & Co KG  | http://omniscale.com
OpenStreetMap WMS and tile services         | http://maps.omniscale.com 

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