I am currently running a process that involves the creation of many "Focal Statistics" rasters in ArcGIS. These rasters use varying-radius circular search areas and calculate three different statistics: Mean, Sum, and Standard Deviation (depending on the input data source). They also must be created in a programmatic manner - either from Python, R, or Bash/Command Line.
I would like to move this to an open source alternative but am having trouble finding an open source equivalent to ArcGIS's "Focal Statistics". The
raster::focal() function in R is terribly slow, and for the size of my data it will not work. SAGA GIS has the 'simple filter' tool, but that will only calculate the Mean, not the other two statistics.
Does anyone have an alternative that replicates the functionality of "Focal Statistics" in a reasonably fast, free, and programmatic manner with a circular search window?