[OpenLayers-Users] zoomToExtent() and zoomToMaxExtent() not working in polar stereographic projection

[Jon Blower]

Dear all,

I fixed my problem.  Turns out that I have to set the maxResolution
property as well.  I have to set this both on the layer (when the
layer is created) and on the map (in the handler for
map.changebaselayer).  I set the value of the maxResolution property
to (top-bottom)/256 where top and bottom are the extremes of the
layer's extent and 256 is the tile size.

Cheers, Jon

On Tue, May 13, 2008 at 2:06 PM, Jon Blower <jdb at mail.nerc-essc.ac.uk> wrote:
> Dear all,
>
> (This is essentially a re-posting of an earlier post, to which I had
> no response.  This is now posted under a more relevant subject line.)
>
> I have an application in which the user can change the base layer.
> Base layers might have different map projections and so I am trying to
> set the projection and maxExtent of the Map object based on the new
> base layer.  I have registered an event handler for
> map.changebaselayer that looks like this:
>
> function baseLayerChanged(event)
> {
>   // Change the parameters of the map based on the new base layer
>   map.setOptions({
>      projection: projCode,
>      maxExtent: map.baseLayer.maxExtent
>   });
>   map.zoomToMaxExtent();
> }
>
> The base layers are set up with different projections (one in
> EPSG:4326, the other in EPSG:32661, which is north polar
> stereographic).  Logging reveals that, when switching to EPSG:32661,
> the maxExtent of the map is being set correctly *but* the true extent
> of the map after the call to zoomToMaxExtent() is not correct:
>
> max extent of map: -10700000, -10700000, 14700000, 14700000
> actual extent of map after call to zoomToMaxExtent: 1999640,
> 1999718.75, 2000360, 2000281.25
>
> hence the map is only covering a very small portion of the true
> maximum extent.  Are there other parameters that I should be setting
> on the base map?  I am not setting resolution, minExtent or zoom
> levels explicitly anywhere in my code.
>
> The same thing happens if I call zoomToExtent() and pass in the
> bounding box explicitly.
>
> Thanks in advance,
> Jon
>
> --
> --------------------------------------------------------------
> Dr Jon Blower Tel: +44 118 378 5213 (direct line)
> Technical Director Tel: +44 118 378 8741 (ESSC)
> Reading e-Science Centre Fax: +44 118 378 6413
> ESSC Email: jdb at mail.nerc-essc.ac.uk
> University of Reading
> 3 Earley Gate
> Reading RG6 6AL, UK
> --------------------------------------------------------------
>



-- 
--------------------------------------------------------------
Dr Jon Blower Tel: +44 118 378 5213 (direct line)
Technical Director Tel: +44 118 378 8741 (ESSC)
Reading e-Science Centre Fax: +44 118 378 6413
ESSC Email: jdb at mail.nerc-essc.ac.uk
University of Reading
3 Earley Gate
Reading RG6 6AL, UK
--------------------------------------------------------------