Network analysis encompasses a wide range of procedures, techniques, and methods that allow for the examination of phenomena that can be modeled in the form of connected sets of edges and vertices. Such sets are termed a network or a graph, and the mathematical basis for network analysis is known as graph theory. Graph theory contains descriptive measures and indices of networks such as connectivity, adjacency, capacity, and flow as well as methods for proving the properties of networks. Networks have long been recognized as an efficient way to model many types of geographic data, including transportation networks, river networks, and utility networks electric, cable, sewer and water, etc. to name just a few. The data structures to support network analysis are covered in [DM4-7] Network models.