Tag: GIS

For every locality on Earth, how far is the nearest hospital? Naively, that's 437 billion great-circle distances. S2 cell indexing reduces it to a single integer range-join: build the index once, and the answer for every place on Earth comes back in seconds. The same primitive also resolves which country, region, and locality each hospital belongs to, in a single pass over one index.

I spent some time playing with the Open Data published by the City of Milan, aiming to visualize public transport coverage. While I managed to create a heatmap, I was left unsatisfied by the data presentation and format. The initiative is promising but could be dramatically improved by adopting modern standards like GeoJSON instead of Shapefiles and including simple preview capabilities.