What does HackerNews think of topojson?

An extension of GeoJSON that encodes topology! 🌐

Language: JavaScript

Not sure but it may be TopoJSON: - https://github.com/topojson/topojson - https://github.com/topojson/topojson-specification

My guess is that Github just recognizes and supports previewing this particular spec.

Yes, we use D3.js and for the map we've built topology file with topojson [1]. This file can be used by D3.js to render SVG map.

[1] https://github.com/topojson/topojson

This can be prototyped pretty quickly using Leaflet to serve the zoom-able tile map and topojson to reduce the size of the overlay data (in this case, train tracks and stations). I haven't tried topojson for a map of the lower 48, but I was getting a 80% reduction in data file size when using it on parcel data. This way, instead of rolling your own tile layer with the data which is a little bit of an involved process, you can just load a topojson file with the data and draw it as a vector layer.

I'm sure there are limitations that make this much more difficult than I'm expressing due to the volume of traffic that hits washingtonpost.com - I'm more remarking on this so if other people are looking to do data visualizations like this they know there is a good dynamic option out there they can try.

http://leafletjs.com/ https://github.com/topojson/topojson