The issues I keep seeing depend on unique combinations of values.

I have three rocktype raster layers for area and they are edge-to-edge (they do not overlap). They each have "VALUE" fields and "COUNT" fields. There's one row of data for each attribute table where "VALUE"=1 where the rock type exists. I guess this is like mask.

What I need to do is combine these three rasters into one with raster calculator using this logic.

rocktype1==1, output value=1

rocktype2==1, output value=2

rocktype3==1, output value=3

Here's what I've tried:

Con("rocktype2"==1, 2) | Con("rocktype1"==1, 1) | Con("rocktype3"==1, 3)
Con("paleo"==1, 2, Con("precamb"==1, 1, Con("tert_quat"==1, 3))) 
rocktype1 + rocktype2 + rocktype3

I continuously get a blank output raster. What am I doing wrong here?

I'm using ArcMap 10.3.

  • (Raster1==1)+(raster2==1)*2+(raster3==1)*3
    – FelixIP
    Apr 17, 2016 at 9:48
  • this expression produced another blank raster output.
    – Stephen E
    Apr 17, 2016 at 22:18
  • Set environment extent to union of inputs.
    – FelixIP
    Apr 17, 2016 at 22:38
  • I've set that parameter in processing extent in envinronment settings and it still produces a blank raster
    – Stephen E
    Apr 17, 2016 at 22:51
  • What does Raster==1 produces?
    – FelixIP
    Apr 17, 2016 at 22:53

2 Answers 2


The raster calculator is working a different way.

First you need to declare your OutRaster that will be saved:

OutRas = Con(...)

Your expression may probably look like this (like your second try, but not sure why you set other names there):

OutRas = Con("rocktype1"==1,1,Con("rocktype2"==2,2,Con("rocktype3"==1,3)))

  • Oops sorry those are the actual names of the rocktypes, just forgot to change them for this purpose. I tried the expression you suggested and the output was only rocktype1.
    – Stephen E
    Apr 17, 2016 at 22:19

As per comment by FelixIP, this expression worked for me:

  • Mark it as solved please to help others
    – FelixIP
    Apr 20, 2016 at 2:02

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