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Raster calculator failed when using setnull function

Zheng_KiYip

Hi Everyone,

I'm using the expression below to try convert all the values that are negative or equal to zero to NoData

SetNull("cov_fdg_ct" <= 0,"cov_fdg_ct")

But it failed to execute with the error message below:

Executing: RasterCalculator SetNull("cov_fdg_ct" <= 0,"cov_fdg_ct") "E:\GIS Data\Thesis modeling\FloodDepthGrids\cov_fdg_c"
Start Time: Fri Jun 12 17:49:33 2015
SetNull("cov_fdg_ct" <= 0,"cov_fdg_ct")
ERROR 000539: Error running expression: rcexec()
Traceback (most recent call last):
  File "<expression>", line 1, in <module>
  File "<string>", line 5, in rcexec
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\sa\Functions.py", line 320, in SetNull
    where_clause)
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\sa\Utils.py", line 47, in swapper
    result = wrapper(*args, **kwargs)
  File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\sa\Functions.py", line 309, in Wrapper
    ["SetNull", in_conditional_raster, in_false_raster_or_constant])
RuntimeError: ERROR 000732: Input Raster: Dataset cov_fdg_ct does not exist or is not supported

Failed to execute (RasterCalculator).
Failed at Fri Jun 12 17:49:34 2015 (Elapsed Time: 0.16 seconds)

I've been reading many posts from those who also got the ERROR 000539 and most of them seem to be due to a syntax error. However, I can't seem to figure out what syntax error is in my simple expression. It would be much appreciated if you can provide some advice!

Thank you!

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Accepted answers

DanPatterson_Retired

You should include spaces between fields, variable names, operators and values as a matter of course to remove/reduce the change that they may become concatenated.

On another note, you are tempting fate by working with rasters data particularly Esri grids, in a folder path that contains spaces...you may and continue to be 'luck' but when you aren't ... remember these words

Good luck

All comments

DarrenWiens2

The first argument is a raster, not a condition. You can use a where clause as the third parameter, though.

SetNull("cov_fdg_ct","cov_fdg_ct","Value <=0")

Craig_AARSC.png

DanPatterson_Retired

Darren is correct.
Always check the help files for syntax and bookmark the help page...for example SetNull syntax

DevinPawluk_2-1782751097136.png

curtvprice

Au contraire, gentlemen.

In the Raster Calculator the rules of arcpy map algebra apply so you can do this.

SetNull("cov_fdg_ct" <= 0,"cov_fdg_ct")

which is converted to the Python below which is then evaluated.

(The <= operator then gets handled by the Python parser to run the LessThanEqual tool, which resolves to the "truth" raster required by the SetNull tool. It's really quite awesome.)

from arcpy.sa import *
out = SetNull(Raster("cov_fdg_ct") <= 0, Raster("cov_fdg_ct"))

My guess is our friend Zheng is having an issue with "cov_fgd_ct" which is for some reason not resolving to a valid raster layer name or raster dataset path.

DanPatterson_Retired

which could only mean that it was typed in manually into the raster calculator otherwise it wouldn't have appeared in the list of rasters .... hmmmm

DanPatterson_Retired

Interesting....

The Results of a test.... Raster in ArcMap 10.3.1 TOC,

Select ... ArcToolbox, Spatial Analyst Tools, Map Algebra...Raster Calculator

random raster appears as a selectable raster.

Enter the expression shown in the image below WITH a where clause, doesn't give an option for where, but what the hey...I put one in. The results from the Results window

Messages

Executing: RasterCalculator SetNull("random","random","VALUE>0.5") F:\Test\x2

Start Time: Fri Jun 12 23:07:49 2015

SetNull(Raster(r"random"),Raster(r"random"),"VALUE>0.5")

Succeeded at Fri Jun 12 23:07:52 2015 (Elapsed Time: 3.25 seconds)

Conclusion....surmization...
The raster calculator whips in the Raster around the inputs ( I should have been more inventive) but uses the where clause

Guess they should separate out raster calculator help or show some examples

EDIT

More inventive now to show what you can also do

SetNull("random",5,"VALUE>0.5)

Results

Messages
Executing: RasterCalculator SetNull("random",5,"VALUE>0.5") F:\Test\x3
Start Time: Fri Jun 12 23:22:30 2015
SetNull(Raster(r"random"),5,"VALUE>0.5")
Succeeded at Fri Jun 12 23:22:34 2015 (Elapsed Time: 4.12 seconds)

Fun with the raster calculator

curtvprice

I guess in this particular case it doesn't work exactly like I said, but the result is the same.

DanPatterson_Retired

I just fine it a little insistent or odd that Raster is whipped around the layer name but NOT the 5 in the Results window output. Why would a layer whose path is know to ArcMap need the raster

Now wrap your head around this one...reading a file from disk...using a layer in arcmap and a where clause

SetNull("F:/test/x","random","VALUE<0.25")

Messages

Executing: RasterCalculator SetNull("F:/test/x","random","VALUE<0.25") C:\Users\Dan\Documents\ArcGIS\Default.gdb\rastercalc

Start Time: Fri Jun 12 23:36:08 2015

SetNull(Raster(r"F:/test/x"),Raster(r"random"),"VALUE<0.25")

Succeeded at Fri Jun 12 23:36:11 2015 (Elapsed Time: 3.27 seconds)

hmmmm....got to love it

curtvprice

> [why] Raster is whipped around the layer name but NOT the 5 in the Results window output.

This is because the SetNull tool can take a straight out integer as an argument, it doesn't need to be a raster layer, raster dataset, or raster object -- no need to wrap in in Raster().

> Why would a layer whose path is know to ArcMap need the raster

I don't believe the F:/test/x needs to be put inside Raster() to work in arcpy -- my guess is whenever the Raster Calculator tools's parser finds a string in that context, it assumes it must be a raster name and wraps Raster() around it - so if you put in "raster" + 5 it will be changed to Raster("raster") + 5 which is valid. (The plus operator can operate on a raster and an integer, but not a string and an integer.)

Zheng_KiYip

Thank you so much for all your advice and responses! Sorry for the delayed reply - I haven't had access to this GIS machine again until today.

To my surprise, I used the same syntax as I did last week and it got executed successfully as below. Any suggestions to what may have changed?

Darren and Dan - Last week before I posted this message, I have also tried the syntax you have suggested (i.e. including the where clause) but I got the same error. However, when I tried again today, it worked also as shown below.

What I have found interesting was that when I took out the space between the = and 0, it no longer works

DanPatterson_Retired

You should include spaces between fields, variable names, operators and values as a matter of course to remove/reduce the change that they may become concatenated.

Good luck

Zheng_KiYip

Thank you Dan! I'll change my directories to have no space to be safe - can't rely on luck!

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