On all interior street lines and exterior boundaries which are street lines of the subdivision, the engineer or surveyor shall set monuments in the street areas, preferably on the street centerline, and located so as to determine the street lines bounding each block. Due consideration shall be given to visibility of monuments one from another, for the purpose intended. (Ord. 89-2 § 2, 1989; Ord. 66 NS § 6.2(b), 1950; prior code § 10-27(d).)