Network models are some of the earliest and most consistently important data models in GISystems. Network modeling has a strong theoretical basis in the mathematical discipline of graph theory, and methods for describing and measuring networks and proving properties of networks are well-developed. There are a variety of network models in GISystems, which are primarily differentiated by the topological relationships they maintain. Network models can act as the basis for location through the process of linear referencing. Network analyses such as routing and flow modeling have to some extent been implemented, although there are substantial opportunities for additional theoretical advances and diversified application.
