(a) Except as otherwise expressly stated in this Zoning Code, for the purpose of measuring the height of a structure, average ground level shall be calculated as the mean (average) ground level at the four principal corners of the subject structure, or the three principal corners in case of a triangular shaped structure footprint.
(b) When a lot is located within a 100-year floodplain, any point located one foot above the regulatory flood level shall be considered to be at the average ground level of the lot.
(c) When a lot is located over an active railway right-of-way, any point located four ft. above the minimum clearance that is required to be maintained above the railway right-of-way and within 110 ft. of the outward edges of the right-of-way, shall be considered to be at the average ground level of the lot.