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I'm trying to see if I can replicate the Esri solar suitability site example from this article.

I fail on the creation of the binary ground raster. I have made a Bare Earth raster from LiDAR ground points, and a surface raster from LiDAR first return points. The tool I use is Greater Than with first return as input raster 1, and ground raster as input raster 2.

I expect a raster with value 1 where the input1 raster is greater than the input2 raster, and value 0 where it is not greater. However, this is the result after the two input rasters:

Input1 - DSM (first return)

Input2 - Raster of Ground points

Result of Greater Than tool

The result should be a ground mask raster like this picture:

enter image description here


Okay, I have the raster I want after doing raster calc + 5 for the DTM and then using a CON expression concerning the DTM and DSM in raster calc to get the ground points raster.

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    Have you tried a Con() statement in raster calculator? e.g. Con(first_return_dem > bare_earth_dem, 1, 0) – Barbarossa Apr 29 '14 at 13:17
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The tool is probably working perfectly -- if the vast majority of the surface (DSM) is greater than the bare earth (DEM), even if only by a few centimeters, the result raster looks correct.

Looking at the ESRI article, however, their ground mask wasn't just "greater than":

assigning a value of 1 for any cell greater than or equal to the bare earth value plus five feet and assigning 0 to all others, which were ground cells

What you therefore need to do is create a raster of the DEM plus five feet (or whatever threshold you want to establish for your own project), using Plus or Raster Calculator. Then, try running GreaterThan again.

  • I didn't know I had to establish a threshold, I thought the plus 5 feet was already an embedded value as a 5ft DEM, but I'll try the plus tool. – MichaelGEO Apr 30 '14 at 14:20

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