The role of the Federal Agency for Cartography and Geodesy (BKG) differs from other authorities in the field of official Surveying and Mapping in Germany. The tasks of BKG are not focussed on the production of maps and datasets but on the provision of spatial reference data to the Federal Administration and the maintenance of the spatial reference systems. Some of the spatial reference data is produced by BKG itself but most of the data is acquired from the Mapping Authorities of the Federal States or from other sources. BKG has a considerable experience in the integration of data sets in national as well as international context. The main challenge lies in the harmonization of data models and legal constraints.