Hi, in the book "Geomorphometry - Concepts, Software, Applications" I've found a short paragraph about the Stream power Index (SPI).
the SPI can be used to describe potential flow erosion related to landscape processes. in the book SPI is defined as: SPI = A x tan(beta) where A is the specific catchment area and beta is the local slope angle. in link [1] there is the SAGA GIS formula. sometimes SPI is also defined as: SPI = ln(A x tan(beta)) my idea for SPI calculation in GRASS GIS may be: A = {accumulation flow by r.watershed} x {ns resolution x ew resolution} beta = r.slope slope anyone ever used/calculated SPI in GRASS GIS? any hints for calculation? [1] http://www.saga-gis.org/saga_module_doc/2.1.4/ta_hydrology_21.html ----- best regards Helmut -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Stream-power-Index-calculation-tp5190756.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user