topic Re: Creating a surface "cap" over DEM in Data Management Questions

Creating a surface "cap" over DEM

808707 — Fri, 17 Jan 2014 10:05:17 GMT

I'm looking into creating a layer showing the depth of material lost from a DEM.

What I want to do is create a "cap" over the DEM. Imagine a flat surface over the DEM before any erosion occured.

Now I can extract elevation values by converting a boundary to points and extracting elevation values.

What I am wondering is what is the best way to extract the highest values at equal intervals across a DEM.

Say I'd like to extract the hightest point from every 50m area of DEM and have this converted to a point showing the location.

I could then create a TIN from these highest location points to give an approximate estimation of the DEM surface before erosion occured.

Does anyone know the best way to go about this or have alternative suggestions on how to do this?

Thanks for any help! 🙂

Re: Creating a surface "cap" over DEM

DuncanHornby — Fri, 17 Jan 2014 14:29:16 GMT

You could use block statistics to find the highest value within your 50m search area then some sort of conditional statement?

Re: Creating a surface "cap" over DEM

808707 — Fri, 17 Jan 2014 15:05:44 GMT

Thanks Hornbydd.

I've just been looking at applying a Maximum focal filter over say a 50m area and then subtracting this from the DEM. These seems to give an indication of the depth of material removed from the landscape.

I'll definitely give your suggestion a go and see what I can come up with.