Streets or Alleys. Where the indicated zoning boundaries are approximately street or alley lines, the center lines of such streets or alleys shall be construed to be the boundaries of such zone.

Lot Lines. Where the zoning boundaries are not shown to be streets or alleys, and where property has been or may hereafter be divided into blocks and lots, the zoning boundaries shall be construed to be lot lines; and where the indicated boundaries are approximately lot lines, said lot lines shall be construed to be the boundaries of said zone, unless said boundaries are otherwise indicated.

Scale on Map—Determination by Commission. Where property is indicated on the zoning map as acreage and not subdivided into lots and blocks, or where the zone boundary lines are not approximately street, alley or lot lines, the zone boundary lines on said zoning map shall be determined by scale contained on such map and where uncertainty exists, the zone boundary line shall be determined by the planning commission. In the event property shown as acreage on the zoning map has been or is subsequently subdivided into lots or blocks by a duly recorded subdivision map and the lot and block arrangement does not conform to that anticipated when the zone boundaries were established, or property is resubdivided by a duly recorded subdivision map into a different arrangement of lots and blocks than shown on the zoning map, the planning commission, after notice to the owners of the property affected thereby, may interpret the map and make minor readjustments in the zone boundaries in such a way as to carry out the intent and purpose of these regulations and conform to the street, block and lot layout on the ground. Such interpretation shall be by written decision, and thereafter the zoning map shall be changed to conform thereto.

Vacated Street or Alley. In the event a dedicated street or alley shown on the zoning map is vacated by resolution or ordinance, the property formerly in said street or alley shall be included within the zone of the adjoining property on either side of said vacated street or alley. In the event said street or alley was a zone boundary between two or more different zones, the new zone boundary shall be the former centerline of the vacated street or alley.

Land Division. When a land division requires the planning commission/city council to make a minor readjustment in zoning district boundaries, a map of this readjustment shall be sent to the Coastal Commission for a determination as to whether it requires an amendment to the zoning map. If no amendment is required, the readjustment shall become effective immediately. If an amendment is required, the requirements of Sections 18.30.010 through 18.30.050 apply.

Use Requirements. No building or part thereof or other structure shall be erected, altered, added to or enlarged; nor shall any land be altered or graded; nor shall any building, structure or premises be used, designated or intended to be used for any purpose or in any manner other than as for purposes and in a fashion that is consistent with the uses hereinafter listed as permitted in the zone in which such buildings, land, or premises are located.

Height Requirements. No building or part thereof or structure shall be erected, reconstructed or structurally altered to exceed in height the limit hereinafter designated for the zone in which such building is located except as provided in Chapter 18.25.

Area Requirements. No building or part thereof or structure shall be erected nor shall any existing building be altered, enlarged or rebuilt or moved into any zone, nor shall any open space be encroached upon or reduced in any manner, except in conformity to the yard, building site area, and building location regulations hereinafter designated for the zone in which such building or open space is located.

Duplicate Use of Open Space and Yards. No yard or other spaces provided about any buildings for the purpose of complying with provisions of these regulations shall be considered as providing a yard or open space for a building on any other building site unless specifically permitted elsewhere in these regulations.