Least Cost Path

Least cost path (LCP) analysis identifies the route between an origin and a destination that minimizes the total cost of traversal across a cost surface. It builds upon cost distance analysisCost Distance AnalysisCost distance analysis calculates the least accumulative cost of traveling from every cell in a raster to one or more... by tracing the path of minimum accumulated cost from a target location back through the cost distance and backlink rasters to the source, yielding a single optimal route.

LCP analysis typically involves three steps. First, a cost (friction) surface is created where each raster cell is assigned a value representing the impedance of traversing it, based on factors such as slope, land cover, proximity to roads, or any domain-specific criterion. Second, a cost distance algorithm propagates outward from the source, computing the minimum accumulated cost to reach every cell. Third, the least cost path is traced from the destination back to the source by following the direction of steepest descent on the cost distance surface.

Transportation engineers use LCP to route highways and pipelines along corridors that minimize construction cost and environmental impact. Conservation biologists model wildlife corridors by finding paths of lowest resistance through developed landscapes. Archaeologists reconstruct ancient trade routes by modeling travel across historical landscapes. Military planners identify optimal movement routes that minimize exposure and energy expenditure. Utility companies route transmission lines and cables to avoid sensitive areas while minimizing cost.

The quality of LCP results depends critically on the accuracy and completeness of the cost surface. Different weighting schemes can produce substantially different routes. LCP produces a single optimal path and does not account for route width, making corridor analysis (which buffers the LCP or identifies multiple alternative paths) a common complementary approach.