Cost Distance Analysis

Cost distance analysis is a raster-based GISGISGeographic Information Systems (GIS) enable users to analyze and visualize spatial data to uncover patterns, relation... technique that computes the cumulative cost of movement from source locations to every other cell in a study area. Unlike simple Euclidean distanceEuclidean DistanceEuclidean distance is the straight-line distance between two points in a plane, computed using the Pythagorean theore..., cost distance accounts for spatially variable friction or impedance, such as terrain steepness, land cover type, road presence, or any factor that makes movement easier or harder. The result is a cost distance surface where each cell value represents the minimum accumulated cost to reach the nearest source.

The analysis requires two inputs: a set of source locations and a cost (friction) surface where each cell value represents the cost of traversing that cell. An algorithm similar to Dijkstra's shortest path propagates outward from source cells, accumulating cost along the least expensive paths. The output includes a cost distance raster (accumulated cost to nearest source) and optionally a cost backlink raster (direction of the least-cost path back to the source), which enables tracing the optimal route from any cell to the nearest source.

Wildlife biologists use cost distance to model habitat connectivity and identify movement corridors for species, assigning high costs to inhospitable land cover and low costs to preferred habitat. Transportation planners model accessibility to facilities, incorporating road networks and terrain. Emergency managers calculate response times across landscapes with varying impedance. Conservation planners identify the least-cost corridors between protected areas. Urban planners assess access equity by computing cost distance from underserved communities to services.

Cost distance analysis captures the real-world complexity of movement across heterogeneous landscapes far more accurately than Euclidean distanceEuclidean DistanceEuclidean distance is the straight-line distance between two points in a plane, computed using the Pythagorean theore.... However, it requires careful calibration of the cost surface, and results are highly sensitive to the friction values assigned to each land cover or terrain class.