The Urban Residence District regulations of the City as differentiated herein and the district locations as shown on the Zoning Map reflect the wide variety of physical and social conditions and characteristics found in the City, to the extent that the range of such conditions and characteristics can be divided into meaningful categories. It is the purpose of these regulations to encourage the creation and maintenance of stable and enduring residential communities by establishing limitations on the use and character of development of land so as to take advantage of, or to avoid conflicts with, natural topography, existing developments, arrangements and location of existing or planned community facilities, and social needs of the community.