[OpenLayers-Users] Changing map projections for WMS layers

[Eric Lemoine]

On Fri, May 2, 2008 at 5:14 PM, Jon Blower <jdb at mail.nerc-essc.ac.uk> wrote:
> Hi all,
>
>  I am developing a WMS-based visualization site using OpenLayers and
>  I'd like to have the capability to change the projection of the map.
>  The map is created using EPSG:4326 but I'd like to be able to change
>  this dynamically to EPSG:32661 (north polar stereographic).  (so that
>  I can display layers from NSIDC, amongst others:
>  http://nsidc.org/data/atlas/ogc_services.html).
>
>  I've tried changing the projection like this:
>
>  map.setOptions({
>     projection: "EPSG:32661",
>     maxExtent: new OpenLayers.Bounds(-10700000, -10700000, 14700000, 14700000)
>  });
>
>  but nothing seems to happen.  The map doesn't change at all, even if I
>  zoom or pan.  Images are still requested using EPSG:4326 and the
>  extent remains unchanged.  (The base layer WMS can accept either
>  EPSG:4326 or EPSG:32661.)
>
>  All the layers on my map are WMS layers.
>
>  Do I need to change the projection of all the layers I'm viewing
>  individually?

yes, I think so.

> If so, what is the purpose of the projection of the map
>  object?

If a layer is created without a projection specified, its projection
is taken from what's specified in the map object.

--
Eric