Network Analysis is closely related to spatial interaction modelling. A set of geographic locations is interconnected in a system by a number of routes. A network refers to a system of lines topologically structured. Networks may be reduced to topological graphs, which are arrays of points connected or not connected to one another by lines. This simplification facilitates the revelation of common topological structures of the networks. The following elements may be identified: nodes, links, and regions. The number of edges (links) in the network, the number of vertices (nodes) in the network, and the number of isolated (i.e., no connecting) networks (sub graphs) are employed to develop a series of topological measures to characterize the network structure. It should be noted that an edge is defined by two nodes. There are two main groups of measures: (1) those based on gross characteristics and (2) those based on shortest-path characteristics. These measures allow a quantitative description of the network and a comparison of one network with another.