topic Re: Raster calculator "if, then, else" statement in ArcGIS Spatial Analyst Questions

Raster calculator "if, then, else" statement

KK2 — Mon, 03 Jun 2019 06:33:32 GMT

Does anyone know if in Raster Calculator it is possible to build more complex condition than with the Con tool?

I would like to create a new column in my attribute table and evaluate the values in this column based on few different columns, e.g:

if value in column A > 50 give me A, then

if value in column B > 50 give me B, then

if value in column C > 50 give me C, then

if value in column D > 50 give me D, else

give me E

Any idea how to do this as one statement in Raster Calculator? Thanks in advance for your answers.

Re: Raster calculator "if, then, else" statement

Anonymous User — Mon, 03 Jun 2019 15:08:46 GMT

Hello,

If you're working with a raster with an attribute table (and it sounds like you are), a better tool might be the Field Calculator, which can incorporate python scripts to process if/else statements. Here's some of the documentation on this:

Fundamentals of Field Calculations - http://desktop.arcgis.com/en/arcmap/latest/manage-data/tables/fundamentals-of-field-calculations.htm#GUID-87E5C668-79E0-40F3-82A0-4A7D6AE8DB13

Calculate Field - http://desktop.arcgis.com/en/arcmap/latest/tools/data-management-toolbox/calculate-field.htm

I don't think there's a way to do this with the Con tool, but maybe others here will have other ideas!

Best,

Lauren

Re: Raster calculator "if, then, else" statement

KevinMayall — Thu, 04 Jul 2019 16:10:35 GMT

You may be better off using the Reclassify tool.

https://pro.arcgis.com/en/pro-app/tool-reference/spatial-analyst/understanding-reclassification.htm

Re: Raster calculator "if, then, else" statement

curtvprice — Sun, 12 Dec 2021 07:50:34 GMT

Reclassify won't work for this as it reclassifies the data in a single value field.

I agree with Lauren that working with Calculate Field in the raster table may be (much) more efficient, but I'm wondering how you got such a "fat" raster table. If the fat table was output from the Combine tool, you may want to skip the Combine tool and do this instead using the five input rasters:

Con("RasterA" > 50, "RasterA", 
    Con("RasterB" > 50, "RasterB", 
    Con("RasterC" > 50, "RasterC",
    Con("RasterD" > 50, "RasterD", 
    "RasterE"))))
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