Digitized mapping of a three dimensional area includes dividing the area into a plurality of primary regions having defined closed contours which are considered flat. Within selected primary regions, one or more secondary regions having defined closed flat contours are identified. Plan coordinate information for the contours of each primary and secondary region is then determined and stored in a file in a hierarchical fashion, where each selected primary region has stored thereunder identified secondary regions thereof. Certain primary and/or secondary regions are also designated for which elevation information is additionally desired. An imaginary grid of lines is defined on each of the designated regions, so that three dimensional coordinate information for each line intersection point of each grid is determined. This intersection point three dimensional coordinate information is stored in a file, whereby elevation information about each of the designated regions is available.