The power of local legislative bodies to enact zoning ordinances to regulate growth within their territorial jurisdictions has long been recognized. Pursuant to several enabling statutes, Virginia cities and counties have chosen various means of implementing this regulatory authority. In response to this trend, Virginia courts have developed general principles for judicial review of zoning ordinances. Simply stated, the purpose of a zoning act must be to promote the public health, safety, morals, or general welfare, to conserve and protect the value of buildings, and to encourage the most appropriate use of the land. If an area is zoned for other purposes or if the locality is arbitrary or discriminatory in applying the ordinance, the locality has exceeded the scope of the police power and the ordinance or its application will be declared void. Zoning ordinances are presumed valid, the burden being placed upon the challenger of the ordinance to show clearly its invalidity. Under no circumstances may a locality, under guise of the police power, impose arbitrary or unreasonable restraints upon the use of private property.