Topology of a Network Data Model
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 the reality as close as possible, both topologically
and geographically. Topologically, each node has been encoded with the
connectivity it permits, such as if a left turn is possible or not (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 which matches to 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.