r.mapcalc contains all the functionality to perform these types of analyses.
See "r.mapcalc: An Algebra for GIS and Image Processing," by Michael Shapiro and Jim Westervelt, U.S. Army Construction Engineering Research Laboratory (March/1991), whose link is located at the bottom of http://grass.itc.it/gdp/html_grass5/html/r.mapcalc.html For example, "peak" would be: r.mapcalc "peak = if( dem > max(dem[-1,-1], dem[-1,0], dem[-1,1], dem[0,1], dem[0,-1], dem[1,-1], dem[1,0], dem[1,1]))" "ridge" would be: r.mapcalc "ridgeVert = if( dem[1,0] > dem[1,-1] && dem[1,0] > dem[1,1] && dem > dem[0,1] && dem > dem[0,-1] && dem[-1,0] > dem[-1,-1] && dem[-1,0] > dem[-1,1])" r.mapcalc "ridgeHorz = ..." r.mapcalc "ridgeFSlash = ..." r.mapcalc "ridgeBSlash = ..." r.mapcalc "ridge = max(ridgeVert, ridgeHorz, ridgeFSlash, ridgeBSlash)" Sincerely, chuck Chuck Ehlschlaeger, Geospatial Science Consultant PERTAN GROUP, http://pertan.com/ [EMAIL PROTECTED], 309-255-2727 http://chuck.ehlschlaeger.info/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jonathan Greenberg Sent: Tuesday, January 15, 2008 7:07 PM To: grass-user Subject: [GRASS-user] "Classic" morphometric feature analysis While I like the generality of the fitted r.param.scale algorithm (indeed, it is used in other software packages as well) to classify various morphometric features, I am trying to find a tool which uses more classic, 3x3 moving window approaches to classify features, e.g. a peak looks like: o o o o x o o o o if x is the largest number; a ridge looks like x o o o x o o x o or o x o or ... (and so on) o o x o x o Does grass contain these older approaches to classifying topographic features hiding in some command? Thanks! --j -- Jonathan A. Greenberg, PhD Postdoctoral Scholar Center for Spatial Technologies and Remote Sensing (CSTARS) University of California, Davis One Shields Avenue The Barn, Room 250N Davis, CA 95616 Cell: 415-794-5043 AIM: jgrn307, MSN: [EMAIL PROTECTED], Gchat: jgrn307 _______________________________________________ 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: 7.5.516 / Virus Database: 269.19.2/1224 - Release Date: 1/14/2008 5:39 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.2/1224 - Release Date: 1/14/2008 5:39 PM _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
