Skip to end of metadata
Go to start of metadata

WPS - Web Processing Service

GeoServer's Web Feature Service (WFS) can return subsets of data but cannot return any changed data. A WPS on the other hand, can modify returned data.  A WPS could perform buffer, reproject, simplify, etc.

GeoServer WPS documentation
GeoServer WPS presentation

GetCapabilities:

Just as WMS, WFS and WCS have a GetCapabilities, WPS has one as well describing the service.  The list of functions is available (such as buffer) in the GetCapabilities response. 

http://giswebservices.massgis.state.ma.us/geoserver/wps?service=WPS&version=1.0.0&request=GetCapabilities

Examples (many more than these are available, this is just a sample):

Aggregate - Count, Average, Max, Median, Min, StdDev, or Sum on an attribute

Area

Bounds

Buffer (Point)

Buffer (Polygon - Quadrant Segments)

Centroid

Difference

Distance

Intersects

isValid

isWithinDistance

Length

Nearest

Overlaps

ReprojectGeometry

Simplify

Union

Unique

Within