1.   In interpreting and applying the provisions of this chapter, they shall be held to be the minimum requirements for the promotion of the public safety, health, convenience, comfort, morals, prosperity and general welfare. It is not intended by this chapter to interfere with or abrogate or annul any easements, covenants or other agreements between parties, except that if this chapter imposes a greater restriction, this chapter shall control.

2.   A district name or letter-number combination shown on the district map indicates that the regulations pertaining to the district designated by that name or letter-number combination extend throughout the whole area in the municipality bounded by the district boundary lines within which such name or letter-number combination is shown or indicated, except as otherwise provided by this section.

3.   Where uncertainty exists with respect to the boundaries of the various districts as shown on the map accompanying and made a part of this chapter, the following rules shall apply:

   A.   In cases where a boundary line is given a position within a street or alley or nonnavigable stream, it shall be deemed to be in the center of the street, alley or stream and if the actual location of such street, alley or stream varies slightly from the location as shown on the district map, then the actual location shall control.

   B.   In cases where a boundary line is shown as being located a specific distance from a street line or other physical feature, this distance shall control.

   C.   In cases where a boundary line is shown adjoining or coincident with a railroad, it shall be deemed to be in the center of the railroad right-of-way and distances measured from the nearest rail of the designated track.

   D.   Where the district boundaries are not otherwise indicated and where the property has been or may hereafter be divided into blocks and lots, the district boundaries shall be construed to be the lot lines, and where the districts designated on the map accompanying and made a part of this chapter are bounded approximately by lot lines, said lot lines shall be construed to be the boundary of such districts unless said boundaries are otherwise indicated on the map.

   E.   In unsubdivided property, unless otherwise indicated, the district boundary line on the maps accompanying and made a part of this chapter shall be determined by the use of the scale contained on such map.