Zoning is an important concept both in real-life town planning, and in the SimCity game.
Zoning in Urban Planning
Zoning is a system of land use regulation which designates the permitted uses of land based on mapped zones, which separate one part of the community from another. Theoretically, its primary purpose is to segregate uses that are thought to be incompatible. In practice, zoning is used as a permitting system to prevent new development from harming existing residents or businesses. Zoning is commonly controlled by local governments such as counties or municipalities.
Zoning commonly includes regulation of the kinds of activities which will be acceptable on particular lots (such as open space, residential, agricultural, commercial or industrial), the densities at which those activities can be performed (low density housing such as single family homes to high density such as apartment buildings), the height of buildings, the amount of space structures may occupy by limiting how close a building may be from the edge of the lot, the proportions of the types of space on a lot (for example, how much landscaped space and how much paved space), and how much parking must be provided.
There are some cities that have been planned from conception, and while the results often don't turn out quite as planned, evidence of the initial plan often remains. Some of the most successful planned cities consist of cells that include park-space, commerce and housing, and then repeat the cell. Usually cells are separated by streets. Often each cell has unique monuments and gardening in the park, and unique gates or boundary-markers for the edges of the cell. The commercial areas naturally become diverse. These differences help instill a sense of place, while the similarities of the cells make each place in the city familiar.
Zoning in SimCity
In SimCity, placement of Residential, Commercial and Industrial zones is the only means to expand the city. Construction will only start within a zone that receives power.
Zones are fixed 3x3 cells for a specific type of growth, and no growth will appear outside the area. All zones will have a chance to have a large building appear, but only residential zones will contain small buildings around the perimeter. The potential growth of the zones is shown underneath the toolkit, as a miniature bar graph.