How can I use geoserver's vendor specific parameters in openlayers?

Question

I want to rotate my map in openlayers. When I set an "angle" as an url option in geoserver openlayers preview, the map is rotated, but I can't seem to find the correct place in my openlayers html-file.

http://docs.geoserver.org/latest/en/user/services/wms/vendor.html

Answer 1

These vendor parameters need to be sent to geoserver from OpenLayers. hence the parameter needs to be put in the options of the constructor of your layer.

So the simple way of constructing our layer is like this:

var wms = new OpenLayers.Layer.WMS("My Layer",
                                   "http://example.com/geoserver/wms",
                                   {layers: "states"});

To pass on vendor parameters to the server, you'll need to do this:

var wms = new OpenLayers.Layer.WMS("My Layer",
                                   "http://example.com/geoserver/wms",
                                   {
                                    layers: "states",
                                    transparent: true, //standard WMS parameter
                                    angle: 45, //vendor specific parameter
                                    buffer:5 //vendor specific parameter
                                   });

These vendor specific parameters will be appended to the WMS requests that OpenLayers makes, and hence Geoserver will respond with an appropriate response.

Answer 2

WMS vender parameter means you can append the parameter to the WMS url directly, just like normal WMS parameters. And in OpnLayers you have the mergeNewParams function.

layer.mergeNewParams({
    'angle': angle_value
});