The above graph represents the basic topology of an urban transport network composed of linked nodes. It has been encoded into a network data model to represent reality as closely as possible, both topologically and geographically. Topologically, each node has been encoded with the connectivity it permits, such as whether a left turn is possible (although this attribute is not displayed here). Further, a direction has been encoded in each link (directional or bi-directional) to represent one-ways. Geographically, each node is located at a coordinate that matches the actual intersection it represents. In addition, the links between each node have been decomposed into several segments (not implicitly shown) to respect the positional accuracy of the road they represent.