Extracting Data

[bepperli at Papin.HRZ.Uni-Marburg.DE]

Hello everyone,
I have to do some work on a 7.5 minutes DEM. Does anyone know how to extract 
or calculate ridges, valleys, drainage divide, drainage channels, slope 
curvature and slope shape ? And where can I get the book "r.mapcalc: An 
algebra for GIS and Image Processing" by M. Shapiro and J. Westervelt? 


Thank you in advance.

J. Bepperling
bepperli at mailer.uni-marburg.de