Chapter 17 Geomorphometry in GRASS GIS

Publisher Summary Geographic Resources Analysis Support System (GRASS) is a general-purpose geographic information system (GIS) for the management, processing, analysis, modeling, and visualization of many types of georeferenced data. This chapter is based on GRASS 6.2 version available for all commonly used operating systems. It includes 2D raster and 3D voxel data support, a new topological 2D/3D vector engine and capabilities for vector network analysis. Attributes are managed in a SQL-based DBMS. Advances in mapping technologies, especially the rapid evolution of airborne and ground-based laser scanning, as well as satellite and airborne radar interferometry are bringing significant changes to geomorphic analysis. The point densities exceed the level of detail required for most applications and digital elevation models (DEMs) with resolutions of 3 m and better are becoming common even for large areas. The high mapping efficiency makes repeated mapping at relatively short time intervals feasible, resulting in multi-temporal DEMs. These developments require new concepts and approaches in geomorphometry. In response, GRASS modules are being further enhanced to accommodate very large data sets produced by the new mapping technologies; new tools are added for efficient handling of very dense elevation or bathymetry data, hierarchical watershed analysis and quantification of land-surface change.