Using Geoserver, is there any way that I can add a predefined string: "No. " to a property: postalnumber?
<sld:Label> <ogc:PropertyName>postalnumber</ogc:PropertyName> </sld:Label>
The SLD spec includes a string concatenation function. Here's an example of how to use it with labels:
The above was tested on geoserver version 2.1.