In their interpretation and application, the provisions of this chapter shall be held to be the minimum requirements adopted for the promotion of the public health, safety, morals, comfort, convenience or general welfare. It is not intended by this chapter to repeal, abrogate, annul or in any way to impair or interfere with any existing provisions of any other law or ordinance previously adopted or which shall be adopted pursuant to law relating to the use of buildings or land; provided, however, that where this chapter imposes a greater restriction upon the use of buildings or land or upon the height of buildings or requires larger yards or other open spaces than are imposed or required by such existing provisions of law or ordinance, the provisions of this chapter shall control.