This law authorizes city legislatures to change or add to the official map of the city in order to lay out new streets, highways parks and even drainage systems. Changes are made subject to adequate notice to those persons noted on last real property tax notice which is to be included in such proposed layout, and are subject to report by planning board who may forfeit right to suspend further action if no response is rendered within thirty days of such reference. Adopted changes become part of city’s official map and are deemed final.