In this paper, we discuss the road distance R and the Euclidean distance u between two points that are distributed over an area. The road distance is defined by the shortest path distance on given networks. In Urban areas, the relation between R and u is given by R=1.3u. And on the regional networks, the shortest path distance is correlated to the Euclidean distance. But the mean value of the ratio R/u varies in case by case.
