How to automatically input a raster value into Raster Calculator?

Question

At Arc 10.5.1 I have a raster containing a single cell, with a value of 9300. From it I need to create an output raster whose cell values decay away from the input raster's cell location, starting with the initial value of 9300.

Using the raster calculator, this equation works correctly:

"out_raster" = 9300/EucDistance("in_raster")

Notice that I have manually typed in the in_raster value, 9300.

Instead of manually entering the value, I now want to use the input raster itself, with its value of 9300. This would allow me to place the equation in ModelBuilder and automate the process with additional single-cell input rasters, whose value may vary from layer to layer (i.e. they're not all 9300). So I replace the text value 9300 with the input raster:

"out_raster" = "in_raster"/EucDistance("in_raster")

I expected the output to be identical to manually entering the input raster's value, but this output raster is useless; it does not display any cells, and its Layer Property values range from -3.40282e-038 to 3.40282e+038, which I think are the storage limits of the raster.

So how can I "automate" this raster equation without having to manually type in each input raster's value?

Answer 1

I believe the issue you are having is to do with the spatial EXTENT of the datasets.

Your initial equation of dividing a constant value (9300) by the euclidean output takes on the extent of the input raster to the euclidean tool, what you are calling "in_raster".

Your second equation replacing the constant with a raster, has it's own extent, which you have not described to us. You say it is a single cell with a value of 9300. Is that a single cell surrounded by NODATA values to the extent of "in_raster" or are they zero values, or is it really just a single cell, if that is the case then the extent is exactly that cell. So the intersection of these two rasters is just one cell, and a number divided by a distance of zero is...

So your raster that will be your single cell of a value 9300 actually needs to be a raster of constant values, the same spatial extent and cell size of the input raster to the euclidean tool.

Answer 2

See https://community.esri.com/thread/22981 for a workflow on the use of the “Get Raster Properties” and “Calculate Value” tools in model builder to get the maximum cell value of an input (would be 9300 in your example), for use in a raster calculation.

Also note the requirement of setting your processing extent as mentioned by the previous poster.