#398: r.watershed with MFD --------------------------+------------------------------------------------- Reporter: mmetz | Owner: grass-dev@lists.osgeo.org Type: enhancement | Status: reopened Priority: minor | Milestone: 7.0.0 Component: Raster | Version: svn-trunk Resolution: | Keywords: Platform: Unspecified | Cpu: Unspecified --------------------------+------------------------------------------------- Comment (by mmetz):
I have submitted a new version of r.watershed to trunk with various changes MFD is fully supported: drainage directions, stream segments, basins, half-basins, RUSLE LS and S factors are all in accordance with MFD flow accumulation. The module is slightly faster and uses a bit less memory. See updated documentation to estimate memory requirements for the ram (all in memory) mode (max 31 MB of RAM for 1 million cells). It is no longer necessary to create a MASK for cells with unknown elevation (NULL values). All cells with unknown elevation (masked or NULL values) are skipped. Zero and negative values are valid elevation values. The color rules generated by the module for flow accumulation have worked for all tests so far and allow visual inspection without manually assigning a color table. I'm using standard deviation and log transform, based on Hamish's (I think) suggestions. Visual output is obsolete but left for comparison. The output drainage direction is slightly changed in case an input map with real depressions was supplied. Previously, real depressions had a drainage direction of -1, but -1 was and is a valid drainage direction indicating a drainage of 45 degree CCW from East towards a cell with unknown elevation. Therefore real depressions have now a drainage direction of 0. As before, if a cell drains due East the drainage direction is 360 degrees, 0 (zero) as drainage direction was unused. RUSLE LS and S factor output maps are now of type DCELL without multiplication by 100. Both factors have always been processed as type double, previously the output maps for the two factors were written out by typecasting from (DCELL * 100) to CELL. Please read the updated documentation before using the new module. Best regards, Markus M -- Ticket URL: <http://trac.osgeo.org/grass/ticket/398#comment:7> GRASS GIS <http://grass.osgeo.org>
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