I have a DEM for a region over which I want to simulate an ecological process. I would like to run several simulations for the same region but I want to alter the topography for the simulations. Most important, I would like to alter the slope (and probably aspect) in various ways. I am working in ArcGIS Desktop and I extracted the slope from the DEM but I have not found any way to manipulate the slope or even access the slope values with their coordinates. Running the process requires several other layers so I would like to remain within the parameters (coordinates, datum, ellipsoid, etc.) of the original DEM.

Is there a way I can alter the slope output, which is currently a raster?

Could I, for example, make the whole region 30% slope with a south aspect?

Is there some other way to generate custom slope files that will be consistent with the other layers?

I am using an ArcGRID DEM from the NED.

Perhaps a different starting point is more appropriate, such as a contour map?

  • Why do you wish to change the slope values you already have? Is there a possibility of some wholesale re-landscaping? – Martin F Dec 24 '13 at 21:25
  • I think you mean "hypsography", rather than "topography". See gis.stackexchange.com/questions/76309/… – Martin F Dec 24 '13 at 21:31

A contour map is rarely a good starting point, especially if you already have a (gridded) elevation model. Contours are cartographic, rather than topographic, features.

Having said that, if the DEM was derived from a contour map to begin with, then maybe you should return to the source.

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