Using OWS Context to describe GML/WFS layers which decimate

[Cameron Shorter]

Tom Kralidis,
As part of OWS4, I'm using rendering GML layers in a web browser, and 
using OWS Context to describe the layers.

The use case I'm having problem with is how to render large datasets 
when the user zooms out, which means you have to render a huge number of 
points.

The usual solution is to decimate the features as you zoom out. Ie, 
reduce the number of points rendered. However, I don't think I can 
describe this using the current OWS Context.

I assume the best solution would be to filter on the zoomLevel, and use 
a different data source for each zoomLevel or resolution, which I 
believe would require a change to the OWS Context spec.

<FeatureType hidden="0">

   <Server service="OGC:GML" version="2.1.2" title="Local">
     <Filter xmlns:gml="http://www.opengis.net/gml">
       <PropertyIsEqualTo>
          <PropertyName>ZoomLevel</PropertyName>
          <Literal>2</Literal>
        </PropertyIsEqualTo>
     </Filter>
     <OnlineResource xlink:type="simple" 
xlink:href="tasmania/TasmaniaRoads2.xml"/>
   </Server>

   <Server>
     <Filter xmlns:gml="http://www.opengis.net/gml">
       <PropertyIsEqualTo>
          <PropertyName>ZoomLevel</PropertyName>
          <Literal>3</Literal>
        </PropertyIsEqualTo>
     </Filter>
     <OnlineResource xlink:type="simple" 
xlink:href="tasmania/TasmaniaRoads3.xml"/>
   </Server>

   <Name>topp:tasmania_roads</Name>
</FeatureType>


I'm open to suggestions here.

-- 
Cameron Shorter
http://cameron.shorter.net