[MapProxy] Adding complete WMS-servers instead of single layers

[Oliver Tonnhofer]

Hi Max,

On 22.02.2011, at 17:04, Max Stephan wrote: 
> 
> I know about those possibilities in Geoserver (although in this case it´s not our server but an external server we are proxying). But our aim is not to group layers into one single layer. Layers should still be separated. It´s only that we want to simplify the configuration. If you imagine having this server with several hundreds of layers and you have to add an entry in the layers-, caches-  and sources-section for each of them it causes a lot of effort. So we´d like to know if there´s another way to handle big amounts of layers from the same server that might change dynamically.

it's not possible to automate that at the moment. And while it wouldn't be that difficult to implement that, I'm questioning the practicality of it (at least partially).

If you dynamically load the capabilities, what should happen when a layer is removed, or renamed? Should the old cache be removed?

Which settings should be used for each cache? A raster layer might require different settings that a vector layer.

And if you are talking about servers with several hundreds of layers, is it really practical to cache each layer separately? Performance degrades with each requested layer. So if your base map requires 20 layers (roads, railways, POIs, etc), then you are better off caching these layers combined in a single cache.

With 1.0 (or even 0.9.1?) you build layer trees and set sources to group layers. You can configure the leaf layers to use the sources directly and the groups layer to use a cache.
That way all users that access the complete base map are using cached map, but they can still request single layers.  

 layers:
   name: base_map
   sources: [base_map_cache]
   layers:
     - name: roads
       sources: [roads_wms]
     - ...


My point is: Setting up MapProxy is easy, but you need some knowledge about your data and how the service will be use, and that's something a script cannot do. Sure, there is room for improvements (e.g. is it really necessary to define the same server for each layer?), but I doubt that the configuration could be fully automated.

Regards,
Oliver

-- 
Oliver Tonnhofer    | Omniscale GmbH & Co KG    | http://omniscale.de
http://mapproxy.org | https://bitbucket.org/olt