(a) It shall be the duty of each county assessor to keep his or her appraisal and assessment data and records current by securing the necessary field data and making changes in valuations as changes occur in land use and improvements, and as errors are discovered and corrected, so that his or her records will at all times show the valuation of property in accordance with the provisions of this subchapter.
(b) Whenever land assessed on an acreage basis is subdivided into lots, the land shall be reassessed on the basis of lots, and whenever land is rezoned for a different use, the land shall be reassessed on the basis of its new classification.