simple addition in raster calculator with incorrect sums

[KyleAntonelis]

Hello: I am building a simple linear additive model.  I've got three reclassed rasters.  Each of them include only the values 0,1,2,3,4,5,6.

When I use the raster calculator to add them, I get what looks to be a raster with correct values for cells from 1 - 18.  However, when I run a quick QC on the output, I see that in many points the cell value is not equal to the sum of the cell values from the three original rasters.

Example: Point X
'tix' cell value = 6
'var' cell value = 6
'bathy' cell value = 5
OUTPUT Raster cell = 18

Any advice would be greatly appreciated.
Cheers

[Robert_LeClair]

Kyle - are your cell sizes in the 3 rasters the same and what is the resampling parameter you're using in the Environment Settings?

Regards,

Robert LeClair
Esri-Denver

[KyleAntonelis]

Robert: The cell size for all 3 rasters is 30x30 meters.  But I have not gone into the Environment Settings at all.  Sounds like that may be where I can fix this?
-Kyle

[KyleAntonelis]

The problem was in the 'Processing Extent'.  I set the extent to the base layer (bathy) and set the 'Snap Raster' to 'bathy' as well.  This solved the problem.  Thanks.