GeoServer supports many SRSs and can transform on-the-fly spatial features from one SRS to another. Sometimes, this may not be what you want; for example, if you are publishing data only in a few SRSs and want GeoServer to be heavily loaded from transformation requests. You will now learn how to limit the list of supported SRS:
Do you know that an SRS is a spatial reference system? If you are not reading the book from start to end, and this acronym sounds confusing, take a look at Chapter 1, GIS Fundamentals.
On your browser, open the WMS capabilities. This is the standard output for the service description. It is an XML file, containing data published, operations supported, and other details. To open it, go to the main page of GeoServer's interface and click on the 1.3.0 link:
You should get a huge XML file. Scroll down to All supported EPSG projections. The following screenshot shows just a few of them; you now have an idea of how many there are:
Now, go to the Service section and click on WMS. Then scroll down and locate the Limited SRS list textbox. Insert the SRS code we will use throughout the book: 4326, 3857, 4269. Then click on the Submit button:
Now repeat the capabilities request and search for the CRS section. Is there any difference? Consider the following screenshot:
We limited the SRS-supported list. This will make the capabilities file clearer, and it will also help some clients to deal with it. You can add or remove SRS from the list at any time, according to the data or maps you have to manage.