(1) Sign height is measured as the vertical distance from the average elevation of the finish grade within a six-foot radius at the base of the sign to the top of the sign, including all backgrounds and support structures, exclusive of any filling, berming, mounding, or landscaping, solely done for the purpose of locating the sign.

(2) If natural grade at the base of a sign is lower than the grade of an adjacent road, the height of the sign may be measured from the top of curb elevation. (See Figure 6-4.)