How To Infer Topology
▻http://bost.ocks.org/mike/topology
As its name implies, #topojson is a topological geospatial data format. In contrast to a geometry, where each shape is encoded with separate (and often redundant) arrays of coordinates, a topology encodes sequences of coordinates in line fragments called arcs that can be shared. The main benefit of a topology is that it improves shape simplification by avoiding artifacts that would be caused by simplifying shapes independently. It also enables applications like #map coloring and selective meshing, and makes the format more compact by removing redundant coordinates.
Mike Bostock explique le principe de fonctionnement de l’algo utilisé dans TopoJSON 1.4.0.
