How to use Set Null in Model Builder?
I am trying to emulate the raster calculator that takes a flow accumulation raster and turns it into a stream raster. Where the number "849840" is the threshold value.
How would I use the Set Null tool in the model builder that will give me the same results?
What would I put in the fields?
If I remember correctly, SetNull (Spatial Analyst) would be done like this to complete your task:
The Input Conditional Raster: dem_fa . (your source raster to operate on)
Expression (optional) would be: VALUE > 849840 . (values above 849840 are evaluated by the tool as True, so will become Null)
Input File raster or constant value: 1 . (constant value to set if False/Not Null, ie your streams will have a value of 1)
Output raster: (your output file name goes here)
Note: be sure to set the Environments (button at bottom of tool). Also, I would avoid using the Default Geodatabase (Default.gdb) and instead set up a geodatabase specifically for this data and its processing.
Chris Donohue, GISP
