[GRASS-user] "Classic" morphometric feature analysis

[Charles Ehlschlaeger]

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/
c.ehlschlaeger at insightbb.com, 309-255-2727
http://chuck.ehlschlaeger.info/

-----Original Message-----
From: grass-user-bounces at lists.osgeo.org
[mailto:grass-user-bounces at lists.osgeo.org] 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: jgrn307 at hotmail.com, Gchat: jgrn307

_______________________________________________
grass-user mailing list
grass-user at lists.osgeo.org
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