I have contour lines, a raster, and a shapefile of the area that needs to be leveled. I have clipped the contour lines and the raster image to the shapefile of the area that needs to be excavated. I was thinking of creating a DEM from the contour lines, but I am not totally sure what to do next.

1 Answer 1


This is more a civil engineering / grading exercise than a GIS one. I'm not sure what your raster is (imagery? a DEM?) so I will ignore that unless you provide more details.

The first thing you need to do is establish what 'level' is. Do you want it absolutely flat, or with some slope for drainage? Then you need to establish how you want to level the area. Will it be filled in to the highest level, excavated to the lowest level, or balanced in between to minimize the amount of earth that must be removed or brought in from off-site.

Once you have that information determined, you'll need an existing surface and a proposed surface, preferably in DEM format (but you could also use a TIN or Terrain Dataset). GIS can help a bit with evaluating proposed surfaces if trying to balance excavation vs buildup (cut/fill). You can experiment with several surfaces to determine the best balance if you're doing that, or just use the tools to establish how much earth to remove. Depending on if you do this in 3D Analyst or Spatial Analyst, there are various surface and cut/fill tools to use.

We have several questions with more specific information on these tools and the operation your want to do (a cut/fill calculation, even if there is no fill):

  • I know that I want the area absolutely flat and I want to excavate the areas to the lowest level. I have created an existing surface DEM but I am not sure how to create a DEM of the proposed surface (lowest lying area with my area of interest). May 2, 2015 at 20:53
  • @SandraMerrick that's easy in this case, since it's a constant value. All you need to do is copy the existing DEM and set the values within your area of interest/cut to that lowest elevation value. This could be done with the raster calculator or Conditional (Con) tool if you have a mask raster of the area (rasterize it if you have a polygon). You could also create a raster that is just the area to be cut with everything outside that as nodata.
    – Chris W
    May 3, 2015 at 21:22
  • @SandraMerrick Don't forget to use the edit button to improve your questions with additional details that people request via comments.
    – PolyGeo
    May 4, 2015 at 21:31

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