In What is SOA (slope of aspect)? @Spacedman explained to me what SOA means. Now I need help to understand how I could work with it and extract the data that I want.

I want to use Qgis (with Grass and Saga) and, if necessary, Python to this task. My goal is to delineate the rim of impact craters. I have been trying a bunch of methods and right now I want to try doing this by working with SOA information.

I know how to make an slope and aspect map from the DEM. But I don't know how to extract the regions of high values of SOA (crater's rim).

  • You take the DEM and then compute the Aspect raster. Then compute the slope of the Aspect raster. That gives you Slope of Aspect. The crater rim is then large values of that. You can do this all from the Raster... Analysis... menu for the aspect and slope, and use the Raster Calculator to threshold the SOA to find the rim. Where in that process are you stuck? – Spacedman Apr 25 '19 at 7:33
  • I don't know how to extract only the rim. It is possible to create a line shp that delineate the rim? – caio villaca Apr 28 '19 at 14:50

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