Links and Resources

3. Looking further into WMS

To gain some more understanding of WMS, open this demo service >http://openlayers.org/en/latest/examples/wms-no-proj.html

A map of Switzerland and its protected areas is presented, and if you zoom out your will notice it is an unprojected map sheet. Still, you can zoom and pan - and every time you change the extent and / or scale, a new image is created at the server and sent to the client.

When you zoom in until you see large pixels it becomes clear that this map is held as a raster file at the server and cannot provide more detailed resolution than available at the host.

Web Map Services = WMS can be based on vector as well as raster data sets held on the server, both are converted into images, but as this app allows extreme zooming the original raster format becomes visible.

This example also provides the HTML and JS code supplied to 'talk' to the server - inspect and try to understand its basic elements!