When confirmed by order of said county legislative authority as aforesaid, or by order of said county legislative authority making any changes decreed by the court on appeal to the superior court, it shall be the duty of the secretary of the district to prepare a correct copy of so much of said base assessment map as includes the lands in the district situated in each county in which the lands in the district are situated, with the assessment classes and ratios properly designated thereon, and file the same with the respective county assessors of said counties for record therein.