The maps were originally created as GIS Shapefiles and then exported as GeoJSON. D3 provides handy functions (d3.geo) to project GeoJSON files to reasonable lo

The maps were originally created as GIS Shapefiles and then exported as GeoJSON. D3 provides handy functions (d3.geo) to project GeoJSON files to reasonable looking maps. You can find all original assets (Creative Commons licensed) here: http://poezn.github.com/us-history-maps/ http://poezn.github.com/us-history-maps/