Slope analysis

Discussion created by l.gratton on Sep 3, 2011
Latest reply on Sep 27, 2011 by erice-esristaff
Hi everyone, here's my situation:
I'm analyzing Mt Cameroon and I need to get the average slope gradient(s) around the volcano edifice. I'm working in arcGIS 9.3 on a SRTM90m DEM of the area.

I don't want that the steep flanks of the volcano can interfere with my calculation of the average slope gradient of the surrounding area; so I was asked to find a way to literally "remove" the portion of the volcano edifice that we don't want to include in the analysis.
I delimited, with a polygon shapefile, the volcano edifice sensu strictu and now I need to find a way to "eliminate" this area from the DEM, in order to calculate the average slope gradient of the surrounding area. I was also asked to get the direction of the inclination of the volcano surrounding areas.
Needless to say that, at the moment I'm not able to accomplish any of these two goals...

so...I'd like to have your help, if anyone has a little time to spend for me!

Thanks a lot to everyone in advance!