The zoning regulations and districts as herein established have been made in accordance with a comprehensive plan to promote, in accordance with present and future needs, the safety, morals, order, convenience, prosperity and general welfare of the citizens of Petersburg, Virginia, and to provide for efficiency and economy in the process of development, for the appropriate and best use of land, for convenience of traffic and circulation of people and goods, for the use and occupancy of buildings, for healthful and convenience distribution of population, for good civic design and arrangement, and for adequate public utilities and facilities, by regulating the location and use of buildings, structures and land for trade, industry, and residence, by regulating and limiting or determining the height and bulk of buildings and structures, the area of yards and other open spaces and the density of use. They have been made with reasonable consideration, naming other things, to the character of the district and its peculiar suitability for particular uses, and with a view to conserving the value of building and encouraging the most appropriate use of land throughout the City of Petersburg, Virginia.