In ArcGIS Desktop I have a slope raster and calculated mean slope per watershed for a fish habitat model. There are zero ("0") values in some subcatchments where no information was available to calculate the mean. This subcatchments have to get the value "NoData", otherwise my model will think zero is a valid input.

How can I change this zero values to NoData?

Before I used the "reclassify" tool. But this does not allow me to keep the decimal numbers of my many means. It only allows for categories. I tried at the symbolgy tab, I can exclude the zeros there and then the maps looks like what I need. But I am afraid this is only the appearance and the zeros are still in the data.


1 Answer 1


Using Raster Calculator you can use SetNull tool as follows:


You need to change RasterName with the name of the raster data. usually if the data is loaded into ArcMap, you can choose the raster layer from the list.

The expression means change the raster data with zero value to Null and keep other values unchanged.

  • 3
    No need to use Raster Calculator. You can use Set Null as a standalone tool
    – GISGe
    Feb 13, 2018 at 14:56
  • Amazing! Thank you so much for your quick help ahmadhanb!
    – Canna
    Feb 13, 2018 at 14:58
  • @GISGe Whether using SetNull as a standalone tool or in Raster Calculator it will do the same job
    – ahmadhanb
    Feb 13, 2018 at 14:59
  • @Heiko You are welcome. Glad it worked.
    – ahmadhanb
    Feb 13, 2018 at 15:00

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