(a) The City is hereby divided into zoning districts, as specified hereinafter.

(b) Within each district there shall be uniform regulation of use of buildings, structure and land, of height, and size of building and structures, of size and width of lots, of dimensions of yard and other open spaces, and of other requirements, as provided in this Zoning Ordinance.

(c) Every parcel of land and every building or other structure in the City, except as otherwise provided by law or by this Zoning Ordinance shall be subject to the regulations, restrictions, and requirements specified for the District in which it is located.

Boundaries of the districts.

(a) The location and boundaries of these districts are hereby established as shown on a map entitled "Zoning Map of Watertown," as dated January 30, 1989, as amended by the amendments thereto adopted May 23, 1989 (the "Zoning Map"), as further amended July 8, 2008 August 18, 2015 and, March 2, 2016, and on file in the office of the City Clerk, which map, with all explanatory matter thereon, is declared to be a part of this Zoning Ordinance.

(b) Any change in the location or boundaries of a district hereafter made through the amendments of the Zoning Ordinance shall be indicated by the alteration of the Zoning Map, and the Zoning Map thus altered is declared to be part of the Zoning Ordinance thus amended.

(c) Where a district boundary is indicated as approximately following, or parallel to, the center line or street line of a street, highway, railroad right of way, or water course, such a district boundary shall be construed as following, or as being parallel to, such center line or street line. Where a district boundary is indicated as approximately following a lot line, such line shall be construed to be said boundary. If no distance is indicated on the Zoning Map for a district boundary running parallel to the center line or street line of a street or highway, such dimension shall be assumed to be 100 feet from the street or, if as determined by the use of the scale shown on said Zoning Map it is at least 20 feet more or less than 100 feet, it shall be as so scaled. When any uncertainty exists as to the exact location of a boundary line, the location of such line shall be determined by the Planning Board.

(d) When a lot in one ownership is situated in part in the City of Watertown and in part in an adjacent city or town, the regulation and restriction of the Zoning Ordinance shall be applied to that portion of such lot as lies in the City of Watertown in the same manner as if the entire lot were situated therein.