Projection 27700 in the OpenGeo Suite SDK GXP

Question

I have some data stored as UK grid references, they display just slightly off alignment on the map after I followed the OpenGEo EXP tutorial using these settings (below) however when I change the EPSG to 27700 for UK grid reference, my map view loads with no layers, or tools visible.

I know it displays ok using 4326 however I thought It is best to follow good practice and amend the projection to the correct EPSG.

  // map and layers
map: {
    id: "mymap", // id needed to reference map in portalConfig above
    title: "Map",
    projection: "EPSG:4326",
    center: [358, 54],
    zoom: 6,

        layers: [{
        source: "ol",
        type: "OpenLayers.Layer.WMS",
        args: ["World map", "http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'}],
        group: "background"
},

Answer 1

If you look at the capabilities of the osgeo server you will see it supports just three projections:

<SRS>EPSG:4269</SRS>
<SRS>EPSG:4326</SRS>
<SRS>EPSG:900913</SRS>

None of which are epsg:27700 - so you can't ask it for a map in 27700, this is why you don't get a map.

You'd need to check the log file and/or firebug to see why you don't get any tools though, I'd guess a typo in the file somewhere.

Answer 2

There are several definitions out there for EPSG.27700. I have listed the circumstances here: Raster incorrectly reprojected to OSGB(27700)

Just to give you an idea why your data was slightly shifted in the first place.

I'm not sure which definition is currently used by OpenGeo suite.