Except as otherwise provided herein, it shall be unlawful to relocate, erect, construct, reconstruct, enlarge, structurally alter, or use any building, structure, or land, except in conformity with the regulations of the district in which such building or structure is located or in accordance with subsection 17-6.1 or 17-6.2. (See also subsection 17-5.12, Nonconforming Uses, Structures or Lots.)