Subject: http://soils.ecn.purdue.edu/~aggrass/grassp/0014.html Re: r.watershed mods Charles Ehlschlaeger (chuck@rap.NCGIA.UCSB.EDU) Thu, 12 Jan 1995 18:28:20 -0800 Messages sorted by: [ date ][ thread ][ subject ][ author ] Next message: Jim Stafford: "Re: r.watershed mods" Previous message: James Darrell McCauley: "r.watershed mods" Maybe in reply to: James Darrell McCauley: "r.watershed mods" James, >For each cell in an accumulation map, my client wants to know how much >came from each landuse in the watershed. Say we have 3 landuses: A, >B, C. Then in r.mapcalc parlance, > accumulation_map=A+B+C >Has anyone done something like this? It would require adding >an additional command line option (landuse=) and would create more >(potentially a large number of) output files (depending upon >how many landuses are present). A simple shell script could do the job. Assuming the landuse map has categories from 1 to 10, the script would be: ***********cut here****************** #!/bin/csh -f set i = 1 while ( $i < 11 ) r.mapcalc "Category$i = if( landuse == $i)" r.watershed elev=dem.name flow=Category$i accumulation=Accum$i @ i++ end END: ***********cut here****************** You will end up with 10 maps: Accum1, Accum2,...,Accum10 where each cell contains the number of cells upstream and including that cell for that category. Add a few bells and whisles, you got yourself a program. BTW, the 3.1+ interactive version of r.watershed can collect basin statistics based on the threshold size for any number of categorical or continuous maps, but the output is ASCII text. I'm not sure that version still exists. _________________________________________________________________________ Charles Ehlschlaeger e-mail : chuck@geog.ucsb.edu Nat. Centr for Geographic Information and Analysis 3510 Phelps Hall Phone : 805-893-8652 University of California Fax : 805-893-8617 Santa Barbara, CA 93106 The Information Superhighway is really an acronym for: "Interactive Network For Organizing, Retrieving, Manipulating, Accessing, And Transferring Information On National Systems, Unleasing Practically Every Rebellious Human Intelligence, Gratifying Hackers, Wiseacres, And Yahoos." _________________________________________________________________________ Next message: Jim Stafford: "Re: r.watershed mods" Previous message: James Darrell McCauley: "r.watershed mods" Maybe in reply to: James Darrell McCauley: "r.watershed mods"