Network Distance Analysis

Network distance analysis measures how far apart places are along a real network — roads, paths, rails — rather than as the crow flies, recognizing that movement is constrained to edges and junctions. Its engine is the shortest-path problem solved by Dijkstra's 1959 algorithm, which finds the least-cost route between locations over a weighted graph and scales up to origin–destination cost matrices between many points. Network distance and travel time are the realistic inputs to accessibility, routing, location, and flow analyses, and their ratio to straight-line distance — the detour or circuity index — itself diagnoses how indirect a network is.