We've seen in earlier recipes that we can query external services for map tiles (WMS) and also for features (WFS). In addition to this, WMS servers can implement the
GetFeatureInfo request. This type of request allows us to, given a point and some layer names that are configured at the WMS server, retrieve information from a feature; that is, we can get feature attributes from a layer, which is rendered as a raster image.
For example, there could be a WMS layer containing parking zones across your region, which can be drawn out as polygons over the map as part of the returned raster tiles. You could listen for a click event on the map and retrieve information from the WMS server in regards to the location that you clicked on. This may return data, such as parking fees, the name of the car park, how many spaces are still available, and so on.
OpenLayers makes this type of feature information request simple with a method called