GeoJSON is an open standard format designed for representing simple geographical features, along with their non-spatial attributes. It is based on JSON, the JavaScript Object Notation.
TopoJSON is an extension of GeoJSON. TopoJSON introduces a new type, "Topology", that contains GeoJSON objects. A topology has an objects map which indexes geometry objects by name. These are standard GeoJSON objects, such as polygons, multi-polygons and geometry collections.
