[MapProxy] proxy by mask?
olt at omniscale.de
Sun Aug 22 11:46:39 EDT 2010
On 21.08.2010, at 19:37, Russ Nelson wrote:
> Hi. I'm trying to edit OSM in New York State. Unfortunately, the
> aerial imagery is split up into 90 different layers. I'd like to use
> code similar to combined_layer as described here:
90 different layers or 90 different WMS servers? If it is the former, than you can just add them all to the layers parameter:
- type: cache_wms
> I'm trying to determine how mapproxy is configured to fetch multiple
> layers. Is it the simple existance of multiple sources in
> config.yaml? Or is it "transparent: true"?
Both. If a layer has multiple sources, then they all will be fetched. Additionally, all but the bottom layer need to be transparent.
> Can I get a few hints about how things are implemented?
> o How are the pixmaps merged into a single image? It looks like
> wms/layer.py:VLayer returns multiple images every time you
> call render.
The WMS layers render methods can return multiple images, they are merged within the WMS server. However, multiple sources for a single cache are combined in mapproxy.wms.cache:WMSTileSource.
> o How are bboxes handled? Are the bboxes for a layer fetched,
> and requests sent to the WMS server only if the request is
> inside its bbox? If so, I can't find the code which does that.
> looked in wms/*, core/layer.py and core/image.py
That's all in mapproxy.core.grid, see get_affected_tiles for example.
> Also, here's my design for the configuration. [...]
If you want to develop some new feature/extension, I strongly suggest you to build it on MapProxy 0.9 and not 0.8.x. Both the configuration and parts of the request/cache/layer-stuff changed.
The 0.9 development is in the default branch of MapProxy: http://bitbucket.org/olt/mapproxy
Oliver Tonnhofer <olt at omniscale.de>
Omniscale - Dominik Helle, Oliver Tonnhofer GbR
Nadorster Str. 60, 26123 Oldenburg
Tel: +49(0)441/9392774-2 (Fax: 9)
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