Cities often have a variety of broad objectives that they wish to achieve in areas like housing, transportation, land use, utilities, recreation, the environment, and culture. These objectives may be expressly outlined in a document called an Official Plan, also known as a Comprehensive Plan, which details a vision for the future growth of the city over a long-term time horizon. 

Transportation is often a key component of Official Plans, image by Marcus Mitanis

The Official Plan contains a number of policies to help guide urban development. For example, Toronto's Official Plan includes policies related to public transit, heritage buildings, and affordable housing. Generally, new development applications must conform to the policies contained within the Official Plan. In many Canadian municipalities, an Official Plan Amendment may be sought if a proponent wants to develop land differently than what is prescribed. These proposed amendments can target specific sites or can apply across the whole city. 

Cover page of Toronto's Official Plan, image via City of Toronto

The Official Plan is implemented through zoning bylaws, which describe the permitted use, height, and density on each property in the city. When objectives in an Official Plan are met, new ones are added. The document is reviewed and updated periodically to ensure relevance as the city develops.