Setting zero values to "NoData"?

Question

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.

Answer 1

Using Raster Calculator you can use SetNull tool as follows:

SetNull("RasterName"==0,"RasterName")

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.