[OpenLayers-Users] Lots of spurious tiles get loaded when changing base layer

[Christopher Schmidt]

On Wed, May 28, 2008 at 10:06:40PM +0200, Eric Lemoine wrote:
> On Tue, May 27, 2008 at 2:42 PM, Jon Blower <jdb at mail.nerc-essc.ac.uk> wrote:
> > Hi,
> >
> > I have an OL2.6 application that uses base layers in different map
> > projections.  The map is initially constructed with a base layer in
> > lat-lon (EPSG:4326).  If I change the base layer to a layer in polar
> > stereographic projection (EPSG:32661) the map loads a whole load (up
> > to 40) of spurious tiles.  This effect can be seen by loading the
> > attached example web page and using Firebug (or similar) to examine
> > the outgoing GetMap requests.  The spurious tiles have a bounding box
> > that is inappropriate for the current zoom level and map extent (this
> > shows up clearly because the extents for 4326 and 32661 are very
> > different in their native units).
> >
> > Registering an event listener for changebaselayer does not help: it
> > seems that the spurious tiles are loaded anyway.
> 
> Based on http://spatialreference.org/ref/epsg/32661/ the bounds for
> 32661 are -180.0 60.0 180.0 90.0 so I don't understand the values
> you're using. (That might not explain the spurious tiles you're seeing
> though)

Those extents are in degrees, not projected units.

Regards,
-- 
Christopher Schmidt
MetaCarta