Geomorphometry

GRASS in Geomorphometry

Import and computing of DEMs

• Grid-based DEMs in various formats can be imported using the r.in.gdal command
• Elevation data represented by digitised contours or measured points can be imported using the v.in.ogr command that supports numerous vector formats
• Data given as an ASCII list of (x, y, z) coordinates can be imported with v.in.ascii
• Very dense ASCII point data (e.g. from LiDAR), can be directly converted to raster using r.in.xyz by performing a binning procedure based on different statistical measures (min, max, mean, range, etc.).

Useful commands

• d.polar
• r.drain
• r.flow
• r.mapcalc
• r.slope.aspect
• ...

References

• Grohmann, C., 2004. Morphometric analysis in geographic information systems: applications of free software GRASS and R? Computers & Geosciences, 30(9-10), pp.1055-1067.
• Hengl, T. & Reuter, H.I., 2009. Geomorphometry : concepts, software, applications, Amsterdam; Oxford: Elsevier.
• Hofierka, J., Mitasova, H. & Neteler, M., 2009. Geomorphometry in GRASS GIS. In Developments in Soil Science. Elsevier, pp. 387-410. Available at: http://dx.doi.org/10.1016/S0166-2481(08)00017-2.
• Le Coz, M. et al., 2009. Assessment of Digital Elevation Model (DEM) aggregation methods for hydrological modeling: Lake Chad basin, Africa. Computers & Geosciences, 35(8), pp.1661-1670.