Raster calculator - problem with number variables in ModelBuilder

Question

When I 'm calculating this expression:

("%Soil organic carbon (t/ha)%" / (10000 * "%Soil depth (m)%" * (Float("%Bulk density (kg/m3)%") / 1000))) * 100

Where:

"%Soil organic carbon (t/ha)%" and "%Bulk density (kg/m3)%" are raster layers

and

"%Soil depth (m)%" is any value or calculator expression with input values: 0.05, 0.15, 0.30, etc.

I 'm geting this error:

ERROR 000539: Error running expression: rcexec() Traceback (most recent call last): File "", line 1, in File "", line 5, in rcexec File "c:\program files\arcgis\desktop10.5\arcpy\arcpy\sa\Functions.py", line 4483, in Times in_raster_or_constant2) File "c:\program files\arcgis\desktop10.5\arcpy\arcpy\sa\Utils.py", line 53, in swapper result = wrapper(*args, **kwargs) File "c:\program files\arcgis\desktop10.5\arcpy\arcpy\sa\Functions.py", line 4480, in Wrapper ["Times", in_raster_or_constant1, in_raster_or_constant2]) RuntimeError: ERROR 000732: Input Raster: Dataset 0.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.050.05 does not exist or is not supported

Failed to execute (Raster Calculator).

Оn the contrary, when I write down "Soil depth" by hand like this, everything is ok

How to fix this problem?

Answer 1

Don't use quote symbols around numeric variables. Using quotes includes the values as strings!

So, where you have 10000 * "%Soil Depth (m)%", this is equivalent to saying 10000 * "0.05". NOT 10000 * 0.05.

When you multiply a string by 10,000, you get that string concatenated to itself, 10,000 times! Something like:

0.050.050.050.050.050.050.050.050.050.050.050.050.050.050.05... etc. Which is what you see in your error message.

So change it to: 10000 * %Soil Depth (m)% (ie, without the double quotes). The whole calculation then would be:

("%Soil organic carbon (t/ha)%" / (10000 * %Soil depth (m)% * (Float("%Bulk density (kg/m3)%") / 1000))) * 100

See also the Raster Calculator documentation which states:

Long, double, or Boolean-type variables will be enclosed in percent symbols (%%). They do not need to be in quotes.

Example: %scale_factor%