For the purposes of this title, the territory of the city is divided into the following zoning districts as shown on the official zoning maps herewith adopted as part of the zoning ordinance of the city:

1. Agricultural district, A-1;
   
2. Residential district, R-1-22;
   
3. Residential district, R-1-10;
   
4. Neighborhood commercial district, C-N;
   
5. General commercial district, C-G;
   
6. Highway commercial, C-H;
   
7. Light industrial district, L-I; and
8. General industrial district, I-G.

The designation of a district on the zoning map of the city shall officially and legally constitute the area so designated and contained within the district as part of said district and subject to the use and building privileges, limitations and conditions relating to such district as set forth in this title and elsewhere in these ordinances. 

When uncertainty exists as to the boundary of any district, the following rules shall apply:

1. Wherever the district boundary is indicated as being approximately upon the centerline of a street, alley or block, or along a property line, then, unless otherwise definitely indicated on the map, the centerline of such street, alley, block or such property line shall be construed to be the boundary of such district;
   
2. Whenever such boundary line of such district is indicated as being approximately at the line of any river, irrigation canal or other waterway, or railroad right-of-way, or public park or other public land, or any section line, then the center of such river or stream, canal or waterway, or of such railroad right-of-way, or the boundary line of such public land or such section line shall be deemed to be the boundary of such district;
   
3. When district boundary lines cannot be determined by the above rules, their location may be found by the use of the scale appearing upon the map;
   
4. When the application of the above rules does not clarify the district boundary location, the planning commission shall interpret the map; and
   
5. When a zoning district boundary cuts through a lot existing at the time of adoption of this zoning code, the use regulations governing the portion of the lot located within the more restrictive zone shall govern the use and development of the entire lot, unless a variance has been granted by the appeal authority in accordance with the limitations of Chapter 16.24., and except for legally existing non-conforming uses and buildings on the lot.