[OpenLayers-Dev] use a layer's maxextent to determine visibility

Christopher Schmidt crschmidt at metacarta.com
Thu Jun 19 08:34:43 EDT 2008

On Thu, Jun 19, 2008 at 11:30:06AM +0200, John Pulles wrote:
> Hi list,
> I'm working on a site where many wms providers are used, covering only a
> relatively small area of the country. Since the maxextent of their layers is
> known, I would like this maxextent to be used when OpenLayers calculates the
> visibility of the layer, thus preventing many getmap requests for empty
> layer images.

Tiles outside maxExtent aren't (or at least, 'shouldn't be') requested,
even if the layer is turned on. calculateInRange is designed to solve
the problem of scale ranges, *not* extent ranges, and changing this
function seems likely to cause problems -- it is assumed throughout the
code that this is designed to change on zoom, thogh I can't say for
*sure* that it wouldn't work otherwise.

Instead, I think we should figure out why tiles that don't overlap with
your WMS maxExtent are being requested. They shouldn't be.

Christopher Schmidt

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