I am working on wildlife and agriculture data in a region where I am attempting to layer the different types of habitat to show the total value of a parcel. For example, I have layers for endangered species habitat, migration corridors, and winter range and have scored each of these differently depending on the value they represent. If a parcel has endangered species habitat it scores as 11, migration corridors score an 8, and winter range scores a 5. I have taken these habitat layers and overlaid a grid layer for each of them but this process is new to me so I am wondering how I should display the values to then result in a map that shows the total value of a parcel. If a parcel has all three habitat types it should score a 24. I am using ArcMap 10.8.1 and working with polygon data.

How do I get a map with the sums of the habitat types using a grid? And do these values go in the grid code in the attribute table?

  • How is your data stored - polygons or rasters? And what software are you using? Can you please edit your question to include these details - that will help others give a more useful answer. Commented Apr 30, 2021 at 17:58
  • Thank you @ycartwhelen I have edited the question to include this. Commented May 3, 2021 at 14:20

1 Answer 1


Unfortunately, your question is still a little confusing. You use the word grid, which leads me to believe that you are actually working with raster data. I may be wrong, but will answer with the raster assumption:

With the Spatial Analyst extension, you have a couple of choices to summarize overlapping raster grids:

  1. The Plus tool will sum, cell-by-cell, the values of two overlapping raster grids.
  2. With the Raster Calculator tool, multiple overlapping raster grids can be summed in one step, in the form of raster_grid_1 + raster_grid_2 + raster_grid_3...

In either case, the summed value will be found in the output raster grid's field value.

Note, however, that the field value is only presented in an attribute table if the output raster grid has a pixel type of integer (if an integer raster grid does not have an attribute table, one can be created with the Build Raster Attribute Table tool). Attribute tables are unavailable if the pixel type is floating point. You can convert a floating point raster to integer with the Spatial Analyst tool Int.

Finally, you used the phrase "grid code": If a raster is converted to a vector format (say with the Raster to Polygon tool), the input raster's value will be contained in the vector output field gridcode (that was a mouthfull!). If you come across a vector layer that contains the field gridcode, that's evidence that the layer had previously existed in raster format.

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