What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?

Question

I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to identify which areas might be rocky hillsides or cliff-faces.

I am wondering what kind of function should I use to best assess this? Slope? Ruggedness?

I am also wondering HOW to go about utilizing the best function to do the job.

I am a beginner GIS student/ecologist, any advice or help would be fantastic! Thanks in advance!

Answer 1

I would say that you're on the right track, and both slope and ruggedness would be useful for you. I'm not sure what angle cliff faces bats prefer but I'm assuming you know this.

To perform a slope analyis, you will need either the Spatial Analyst Extension or the 3D Analyst Extension. You want to run the Slope Tool. Once you've performed the slope analysis, you can then use the Con tool (requires Spatial Analyst) to pull out the areas of steep land. There may be other tools in the Conditional Toolset which might be useful as well.

In terms of Ruggedness, you might want to check out this post on how to calculate it. @whuber has a good answer for performing the calculation in ArcGIS.

Hope this helps.