Geomorphological mapping using object-based analysis and ASTER DEM in the Paraiba do Sul Valley, Brazil

The aim of this work is to develop an object-based methodology for semi-automatic geomorphological mapping. The study area is the municipality of Sao Jose dos Campos, located in the Paraiba do Sul Valley, Sao Paulo State, Brazil. A multilevel hierarchical semantic network driven by a set of multispectral, geomorphometric and texture variables is used. The geomorphometric and texture variables are extracted from a digital elevation model (DEM) generated from a stereo pair of advanced spaceborne thermal emission and reflection radiometer (ASTER)/Terra images. The DEM accuracy is evaluated and its root mean square error (RMSE) is found to be 9.38 m. The validation of the geomorphological map is accomplished by means of object-based statistical indices derived from an error matrix, obtained by a comparison between the classified scene and a reference map produced by visual interpretation. The object-based approach is found to be effective for geomorphological mapping.