Re: Apply regression for only certain cell values

AimeeRoach

Thanks very much, problem solved!

I have one other question, regarding the raster calculator. I'm using the raster calculator to input a regression equation that I've created from my data, using the output I created with the euclidean distance calculator as the x value for the equation. However it predicts unrealistic values outside the range of what I know is possible for the variable I'm measuring. I'm wondering if there's a way that I can limit the output of the output from the raster calculator to only predict within values I know are possible? For instance limit the prediction to within -4 to 1, rather than allowing the calculator to predict values of up to -16, etc.

curtvprice

  For instance limit the prediction to within -4 to 1, rather than allowing the calculator to predict values of up to -16, etc.

SetNull and Con can do a lot of handy things like this with cell values. Reclassify is also useful, but Con and SetNull are more flexible and work well with float and integer rasters.

For example, if this is your regression equation, go ahead and calculate all the values to a grid called "results":

(5.0 * factor1) + 0.45

To set all cells outside the range, to NoData you could then do this with a second Raster Calculator run:

SetNull("results" < -4 or "results" > 1, "results")

You can get fancier, for example, to "saturate" at those values and make all the areas below -4 stay at -4, you could do this:

Con("results" < -4, -4, Con("results" > 1, 1, "results")

Hope this helps!