Maps Visualization, GeoJSON, TopoJSON

mapschool: a free introduction to geo:

GeoJSON

GeoJSON - Wikipedia, the free encyclopedia

geojson.io

Let’s Make a Map by Mike Bostock

mbostock/topojson

API Reference · mbostock/topojson Wiki

Using GeoJSON with Leaflet - Leaflet - a JavaScript library for mobile-friendly maps

Ogre - ogr2ogr web client
Ogre is a web client (service) that translates spatial files into GeoJSON using the ogr2ogr command line tool for use in JavaScript web applications and frameworks.

How to convert Shapefiles to GeoJSON maps for use on GitHub (and why you should) » Ben Balter