The following standards shall be used to determine the area and height measurements for all signs in the City:
(a) The area of a sign shall be computed by means of the smallest square, circle, rectangle, triangle, or combination thereof that will encompass the exterior display limits of a sign, but not including any supporting frame or bracing.
(b) The sign area for a sign with more than one face shall be computed by adding together the area of all sign faces visible from any one point.
(c) In the case of irregularly shaped three dimensional signs the area of the display surface shall be measured on the plane of the largest vertical cross section.
(d) The height of a sign shall be determined by measuring the vertical distance between the top part of the sign to the elevation of the ground beneath the sign prior to construction, excluding additional elevation added by creation of berming or mounding. If the grade prior to construction cannot be determined, the elevation of the base of the sign shall be computed using the elevation of the nearest point of the crown of a public street or the grade of the land at the principal entrance to the principal structure on the premises, whichever is lower.