State borders in ETRS89 coordinates – reality or fiction ?

Common unique ETRS89 coordinates of the state boundaries are crucial for cross-border data harmonization for international projects. In the frame of European Location Framework (ELF) project Czech Office for Surveying, Mapping and Cadastre (CUZK) cooperates with Poland on egde-matching on the state border. During the preliminary phase of the project was some difficulty identified. If the state boundary is measured and administered in the national coordinate system, the accuracy of the transformation into the ETRS89 is influenced by discrepancies of the local trigonometric network, which results in two slightly different state boundaries. Final solution for Europe – international treaties on the state borders based on the ETRS89 coordinates – is necessary, but it will take years.