R script to demonstrate how to create a heatmap using GeoJSON spatial data.
Downloding json files via web links is also exemplified.
Links to the source data files used in the script:
NYC school attendance data: https://data.cityofnewyork.us/resource/vww9-qguh
NYC school districts spatial data: https://data.cityofnewyork.us/resource/cuae-wd7h