The centerline of a road being altered or established shall be the centerline of survey. Each angle or change of direction must be accurately determined, and the length of each course carefully measured. The distance shall be ascertained to all watercourses and summits of hills along the line thereof where an expenditure of public money or labor will be required. The boundary line of each side of the road shall be marked by substantial stakes driven on the summits of hills, crossings of watercourses, and other convenient places, and in the prairie at reasonable intervals. All stakes driven to indicate said boundary lines shall be marked C. R., the initial letters of County Roads, on the sides facing the road and angles thereof.