Unless otherwise shown, the district boundaries shall be construed to coincide with the center lines of streets, alleys, parkways, waterways and main track or tracks of railroads.

Where such boundaries are indicated as approximately following the property lines of parks or other publicly owned lands, such lines shall be construed to be such boundaries.

In all cases where a district boundary divides a lot in one ownership and more than 50% of the area of such lot lies in the less restricted district, the regulations prescribed by this chapter for the less restricted district shall apply to such portion of the more restricted portion of said lot which lies within 30 feet of such district boundary. For purposes of this section, the "more restricted district" shall be deemed to be that district which is subject to regulations which prohibit the particular use intended to be made of said lot or which regulations require higher standards with respect to setback, coverage, yards, screening, landscaping and similar requirements.

In all cases where a district boundary line is located not farther than 15 feet away from a lot line of record, such boundary shall be construed to coincide with such lot line.

In all other cases, where dimensions are not shown on the Zoning Map, the location of boundaries shall be determined by the use of the scale appearing on such map.

Except as permitted by § 224-89, no building shall be erected, moved, altered, rebuilt or enlarged, nor shall any land or building be used, designed or arranged to be used for any purpose or in any manner except in conformity with all regulations, requirements and/or restrictions specified in this chapter for the district in which such building or land is located.

No yard or open space required in connection with any building or use shall be considered as providing the required open spaces for any other building on the same or any other lot.

Except as permitted hereinafter, no lot shall be formed from part of a lot already occupied by a building unless such building, all yards and open spaces connected therewith and the remaining lot comply with all requirements prescribed by this chapter for the district in which said lot is located. No permit shall be issued for the erection of a building on any new lot thus created unless such building and lot comply with all the provisions of this chapter. In cases where two or more buildings erected prior to the effective date of this chapter occupy one lot, the division of said lot in such a way as to establish a separate lot for each of said buildings may be authorized, upon application, by the Board of Appeals. In considering such application, the Board shall endeavor to secure minimum possible deviations from the provisions of this chapter.

The minimum lot width or area regulations shall not apply to any lot with an area and/or width of less than that prescribed herein provided that:

Nothing contained in this chapter or any subsequent amendment hereto shall require any change in the plans, construction or designated use of a building complying with existing law, a permit for which had been duly issued and the construction of which shall have been started before May 22, 1958, the date of first publication of notice of the public hearing on this chapter, or before the date of first publication of notice of the public hearing on any subsequent amendment hereto, and the ground-story framework of which, including the second tier of beams, shall have been completed within six months of the date of the permit, and which entire building shall have been completed in accordance with such plans as have been filed, within nine months from the date of passage of this chapter or any applicable subsequent amendment thereto.