(a) The owners of land lying beyond the confines of municipal corporations, which have not theretofore been subdivided as additions or subdivisions of any city or town, may have their lands surveyed and divided into numbered plots by a competent surveyor, who shall make a plat thereof.
(b) The plat, when duly certified by the surveyor, shall be filed for record with the recorder of deeds, and a copy of the plat shall be filed with the county assessor of the county in which the lands are situated.