Third video in a series on how to use ModelBuilder in ArcGIS 10.3 to automate geoprocessing tasks. The goal is to build our model to take Boston 311 data, map the data, aggregate it by neighborhood, calculate a series of normalized indices, and output properly symbolized feature layers. In this video we add fields to the output layer to calculate area in square miles, and then calculate our indices of reports per square mile and reports per person.