Calculating spatial correlation between two datasets using ArcMap and Spatial Analyst

Question

I am using ArcMap and the Spatial Analyst extension.

I am trying to find a correlation between my raster datasets. For example, for Net Primary Production (NPP) model I used too many input datasets such as solar radiation, soil, NDVI, etc... So I wanted to find which dataset represents the result NPP map most.

I tried to convert them to ASCII format so that I can analyze them in statistical software like SPSS but when I convert it, the output data .txt size became 1.3 GB which is pretty big for a text file. So I couldn't open it with or without any kind of big text file reader software.

Do you have any ideas about it?

Answer 1

If you are running ArcMap or certain versions of ArcPro you can install the Gradient Metrics Toolbox. There are tools that provide two ways to tackle this problem: 1) calculate global correlations between rasters (representing a single correlation coefficient) or 2) Calculate the local correlations thus, returning a raster representing correlation between rasters within an n sized window. They obviously tell you different things but, it is up to you to decide how global verses local correlation addresses your question.