What’s more awesome is that underneath, GitHub is using two of my favourite mapping resources: LeafletJS and MapBox vector tiles to render the map. While Leaflet is being used to render the GeoJSON data, GitHub uses customized MapBox tiles based on OpenStreetMap as the basemap.
You can add all sorts of GIS data as a point, polyline or polygon, as long as it is in
GeoJSON. To make matter more interesting, these features are fully customizable and you can edit the way your data is displayed on the map such as changing the colour, providing custom icons for markers and user interactivity.