Zoning Map. The boundaries of the districts enumerated in § 17.13 of this chapter are hereby established as shown on a map titled "Zoning Map, City of Nekoosa, Wisconsin," dated January 5, 1988, which is adopted by reference and made a part hereof. The map shall bear upon its face the attestation of the Mayor and the City Clerk and shall be available to the public in the office of the City Clerk. Changes to the districts subsequent to January 5, 1988, shall not be effective until entered and attested on this certified copy.