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I'm trying to design a heatmap overlay bounded within four given coordinates with OpenLayers using WMS protocol to communicate with my GeoServer instance, where my data and SLD heatmap description reside. I can basically do it but I incur in two problems I'd like to fix:

  1. I have to set "singleTile: false" in the WMS options, and this causes the heatmap to be recomputed for each sent tile, and thus have some discontinuity. Here is an example of what I mean with discontinuity
  2. I select bounds using maxExtent option, which causes entire tiles to be displayed, even if I'm only interested in a small portion of the selected tile.

Here is my code from the javascript side:

  format = 'image/png';
  heatmap = new OpenLayers.Layer.WMS(
"Rainfall", "http://localhost:8080/geoserver/postgis/wms",
  LAYERS: 'postgis:rainfall',
  format: format,
  transparent: true
  singleTile: false,
  visibility: true,
  buffer: 0,
  maxExtent: new OpenLayers.Bounds(-15000000, -6000000, -8000000, 2000000),
  isBaseLayer: false

My questions are: What is the right way to do what I'm trying to do? Is it possible to use WMS protocol to do that?, should I do it at a lower level(maybe in the SLD)?

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