Abstract: The raster terrains can be deformed to sparse networks and dense networks according to different neighborhood structures.The least-cost path problems in sparse networks are analyzed,modeled and resolved using the Dijkstra algorithm.Simultaneously the ones in dense networks are analyzed,modeled and resolved by simulated annealing algorithm.The accuracy and efficiency of the results got from the experiments of the two methods were compared and analyzed thoroughly.And the Dijkstra algorithm is proved to be more suitable for least-cost path planning in raster terrains.