Section 17.  Subject to uniform procedures established by law, a local governmental subdivision may (1) adopt regulations for land use, zoning, and historic preservation, which authority is declared to be a public purpose; (2) create commissions and districts to implement those regulations; (3) review decisions of any such commission; and (4) adopt standards for use, construction, demolition, and modification of areas and structures.  Existing constitutional authority for historic preservation commissions is retained.