In all districts any existing building or other structure or any tract of land or use existing on February 22, 1979, or the effective date of any applicable amendment to this chapter, which is not in conformity with the regulations for the district in which it is located shall be deemed nonconforming, except for any building or structure that is in violation of any preceding ordinance, and subject to the appropriate regulations of this chapter governing such nonconforming uses, lots and structures.