Focal Diversity for Pro

Blog Post created by bgerlt-esristaff Employee on Mar 29, 2019

Diversity Tools is a bit of an experimental python toolbox that currently contains only a single tool, Focal Diversity. 


The tool can calculate two diversity indexes for rectangular focal areas based on a single band raster input.  The Shannon Diversity Index, often referred to as Shannon-Weaver or Shannon-Wiener Index and Simpsons Index of Diversity or Inverse Simpsons Index are both popular diversity indexes in ecology applications and are commonly used to provide a measure of species or habitat diversity for non-overlapping areas. Like the Centrality Analysis Tools published last year, Diversity Tools is based on work performed during the Green Infrastructure project a few years back.  The ArcGIS Focal Statistics tool, available with Spatial Analyst, calculates several statistics for raster focal neighborhoods, including variety, but not diversity.  Both Focal Statistics with the Variety option and Focal Diversity calculate a value for the central pixel in a sliding rectangular window based on the unique values within the focal window. Unlike Focal Statistics, Focal Diversity does not require a Spatial Analyst license.


I look forward to hearing of your use cases and suggestions for improvements.  I am already thinking about a Zonal Diversity tool similar to Zonal Statistics if there is interest.