§ 12. Engineering survey.

After tentative approval or conditional approval of the preliminary plat the subdivider shall cause the subdivision to be surveyed, staked and monumented by a qualified land surveyor or registered professional engineer. Where permanent monuments are not already in place, monuments consisting of iron rods at least one-half inch in diameter and forty-eight inches in length and encased in concrete at least four inches in diameter shall be set at the intersections of all boundary angles of the subdivision and at intersections of street, alley and boundary lines, all flush with the finished grade except that those within a roadway may be set at subgrade level.

Iron roads of one-half inch or more in diameter and twenty-four inches or more in length, set flush with the finished grade, shall be located at the boundary angles, intersections and points of curvature of all lot, street, alley and boundary lines, where permanent monuments are not set.

The plat may then be prepared in final form, and both survey and plat shall conform to the preliminary plat as tentatively approved or conditionally approved, including any required modifications.