On 2012.03.22, at 3:16 AM, Andrea Aime wrote:
> On Wed, Mar 21, 2012 at 7:51 PM, Glenn Brauen <glenn@...> wrote:
> I'm wondering about the status of support for parsing the UserDefinedSymbolization element of WMS GetCapabilities responses.
> Scanning the geo-tools-devel list archives, I can see a few commits over the years referring to the UserDefinedSymbolization keyword. But it appears to be only partially implemented in both versions 8.0 (svn checkout from yesterday) and 2.7.4. I think enough is there so that the parsing won't complain about finding the element but it is ignored if found. I found no issue in Jira about this.
> I'd like to use Geotools to parse and interrogate these elements and would be willing to contribute to seeing this supported. I've been looking at the software and have a pretty good idea of what's required.
> Are there any plans for this?
> Let me summarize, you are planning to modify the existing wms client to report if the server can support
> used defined symbolization, and in that case, send down to the server a request with a SLDBODY or
> a POST request with full XML GetMap?
> And the style would come from ... where? Directly from the MapContext/MapContent (mind the API
> change on trunk) layer?
> I don't believe there are any plans for that right now, a contribution in that direction would be
> certainly welcomed. Some design discussion on the ml before getting down to coding is
> recommended in order to build a patch that gets actually accepted in the code base.
I guess what I'm proposing is just the first step on the path you are imagining. :)
For my plans right now, I would like to use GeoTools to help me figure out the capabilities of WMS to support user styled layers but I am not currently planning to issue the SLD-specifying GetMap requests from GT. Instead, the GT parsing code will be part of a servlet providing information about services and the GetMap requests themselves would come from a client of the servlet (possibly using OpenLayers).
So what I'm proposing is to add the capability for parsing the UserDefinedSymbolization attributes and to create a new class (child of WMSCapabilities) to provide access to those parameters after a GetCapabilities document has been parsed. I would add public interfaces to WMSCapabilities to get/set the userDefinedSymbolization object.
The main files that I think would be affected are:
and I would add a new class called UserDefinedSymbolization in package org.geotools.data.wms as a container for the parsed attributes.
Most of it looks pretty straightforward to me. But I have not yet looked closely at how the schema tokens in WMS.java are generated so I still need to figure that out.