The Federal Agency for Cartography and Geodesy (BKG) has supplied national geo base data in the form of Verwaltungsgebiete VG25 from 31.12.2013. This data is now used by the IOER Monitor. Each updated version of VG25 is derived afresh from the Basis DLM, which includes all corrections to boundaries as provided by the state survey authorities. Therefore, minor geometric disparities in the boundaries of administrative units over various timeframes may appear even if there have been no changes in the actual administrative area.