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Suitability analysis with raster calc/weighted overlay

Question asked by wcvanzyl on Aug 24, 2017
Latest reply on Aug 24, 2017 by Dan_Patterson

I have various suitability layers (raster) with cells classified into 1, 2, 3, 4, 5 with 5 being the most suitable.


When I combine my layers and I use Spatial analyst Raster Calculator in ArcGIS (10.3), with weighting multiplied as in layer1*0.2 + layer2*0.2 + layer3*0.2 +layer4*0.2 + layer5*0.2, the output is not what I expect: it creates values between 1.2 and 4.4 (floating points values).


However, using the exact same layers and same weight schemes with weighted overlay, it keeps the 1, 2, 3, 4, 5 scheme.


Can anyone explain why this is happening? I've watched tutorials where only 2 classes were used, say 50 and 100 with 100 being most suitable and using raster calculator, it keeps the 50 and 100 range. But why won't mine work?


weighted overlay vs raster calc output


Much appreciate any feedback