[OpenLayers-Dev] Muliple projections

[Christopher Schmidt]

On Thu, Feb 12, 2009 at 08:51:04PM -0000, David Cordner wrote:
> Hi
> 
> I am fairly new to GIS and very new to OpenLayers so appreciate any
> advice you can give.
> 
> I am going to be creating an app which will have a OpenStreetMap
> BaseLayer and I'll then be dynamically loading vector layers (coloured
> government boundaries). The vector layer will be need to use projection
> EPSG:27700. 
> 
> I'm not 100% sure how projections work, do I need to use the same
> projection on each layer and if so how do I do this?

Have you read http://docs.openlayers.org/library/spherical_mercator ?
http://docs.openlayers.org/library/spherical_mercator#reprojecting-vector-data
,
http://docs.openlayers.org/library/spherical_mercator#serializing-projected-data
both seem relevant.

Regards,
-- 
Christopher Schmidt
MetaCarta