It is also possible that the region was not set to the geographic coordinates of the dem or slope map when performing the r.mapcalc. r.slope.aspect is one of the few programs to default to extent and resolution of the original map, not the current region.
Chuck Ehlschlaeger, Associate Professor of Geography Western Illinois University 215 Tillman Hall, 1 University Circle, Macomb, IL 61455 [EMAIL PROTECTED], phone: 309-298-1841, fax: 309-298-3003 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin Landa Sent: Wednesday, November 21, 2007 1:23 PM To: nishith datta Cc: GRASS users list Subject: Re: [GRASS-user] extract by attribute from a dem [please cc to grass-user ml...] 2007/11/21, nishith datta <[EMAIL PROTECTED]>: > thanks for the prompt reply, > sorry it didnot work either ? > any ideas why ? > can I somehow see the data in the raster layer - slope original. I mean the > count of pixels and the categories i.e the slope value against each > category. in spearfish $ r.slope.aspect ele=elevation.dem slope=slope $ r.stats slope nsteps=10 -c --q 0-5.252012 731997 5.252012-10.504024 775215 10.504024-15.756036 545337 15.756036-21.008047 335709 21.008047-26.260059 152262 26.260059-31.512071 56475 31.512071-36.764083 12735 36.764083-42.016095 1251 42.016095-47.268107 117 47.268107-52.520119 9 * 358245 $ r.mapcalc 'new=if( slope <= 20, slope, null())' $ r.stats new nsteps=10 -c --q 0-1.999213 156159 1.999213-3.998426 346518 3.998426-5.997639 352206 5.997639-7.996851 314379 7.996851-9.996064 277200 9.996064-11.995277 237015 11.995277-13.99449 210267 13.99449-15.993703 178020 15.993703-17.992916 148995 17.992916-19.992128 270 * 748323 > may be there is something wrong with the slope map. > Also won't changing 20 to 90 in the expression if(slopeoriginal <= 20, > slopeoriginal, null()) give me the original map again? > thanks > nishith -- Martin Landa <[EMAIL PROTECTED]> * http://gama.fsv.cvut.cz/~landa * _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.2/1142 - Release Date: 11/20/2007 5:44 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.2/1142 - Release Date: 11/20/2007 5:44 PM _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
