[Cross-post Python forum] Finding saddle points in a grid?

Question

Sorry for the cross-post, not sure where this belongs.

See http://forums.arcgis.com/threads/73854-Finding-saddle-points-in-a-grid

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Hello all!

I would like to be able to identify saddle points in my grid.

Does anyone know of a method to do this? Search has led me in the way of Numpy. Would that be the right direction to go or can this be achieved with Spatial Analyst?

Thanks!

MapMan1 · Answer

Stefan, I am trying to find/locate saddle points in a DEM as well. Did you ever find a solution? If so, can you point me to it or describe it to me? You can email me at jed.flint -at- yahoo.com

curtvprice · Answer

I geographical terms, I think of the saddle point as a mountain pass like in the second picture in the link. From that point, the surface curves up in one direction and down in another.

You may want to look at the Curvature tool. Comparing that value with some other measures (slope for example) may help you isolate the area you're interested in.

SebastianSantibanez · Answer

I guess that you could fit some helmets to your geographical features and obtain your saddle point by analyzing the deterministic surface you would obtain from that fitting.  
Another suggestion I would explore is passing a low pass filter through your raster so your geography gets smoother.