An application of QGIS used to develop models utilizing a large variety of powerful Geoprocessing tools via a GUI.
A model is a sequential set of Geoprocessing tools used to perform various analysis. The output of one tool can be used as an input for another. All this is done via a GUI, removing the need for the user to write any code. This is perfect for new and old users of QGIS to simply select the required algorithms from a list.
Note: "SEXTANTE" has been replaced with "Processing".
Reference: SEXTANTE Spatial Data Processing Framework