Splitting polygons by a percentage

Discussion created by salford10 on Jul 16, 2012
Hi Guys,

I'm having some difficulty with a task I am trying to perform and I wonder if anybody can help.

I have a large number of glacier polygons and I am trying to segregate the lower portions of each glacier all at once. Approximately I want to split the bottom 30% of each glacier away from their bodies. In addition to the glacier polygons I also have a DEM of the area of interest.

I have had a chat with one of my colleagues and he thinks it may be possible by utilising a conditional statement in the raster calculator and maybe some zonal statistics. Roughly something like DEM > Min and < Min + range x 0.3. The DEM file would be a mask of the glacier polygons.

I am still a bit of a novice when it comes to constructing these statements and I wonder if anybody could help. Alternatively if you could think of any other options it would be much appreciated.