Detailed gravimetric quasigeoid QGZÚ-2013

The detailed gravimetric quasigeoid model QGZÚ-2013 represents a transformation surface enabling the conversion between orthometric heights H in the Baltic Vertical Datum – After Adjustment (Bpv) and ellipsoidal heights h determined in the European Terrestrial Reference System 1989 (ETRS89), realisation ETRF2000, above the Geodetic Reference System 1980 (GRS80) ellipsoid. The data content consists of height anomalies (zeta) provided at the nodes of a regular 3″ × 3″ grid in ETRS89 geographical coordinates. The height anomaly represents the transformation relationship expressed as: h = H + zeta. The total root mean square error of the height anomaly zeta is 0.01 m within the territory of the Czech Republic. In mountainous terrain and border areas (within 10 km of the state boundary), the error may reach higher values, but not exceeding 0.03 m. The quasigeoid model was derived using a combined regional solution of the linear gravimetric boundary value problem for the disturbing gravitational potential of the Earth. The computation made significant use of the revised complete dataset of detailed gravimetric survey points collected during geophysical surveys carried out between 1950 and 2010, together with additional data sources. The model is primarily intended for specialised geodetic applications requiring detailed knowledge of the local behaviour of the height anomaly. In such applications, it facilitates the determination of local transformation parameters necessary for the mutual conversion of heights between the Bpv and ETRS89 reference systems. Please note that due to differences in processing methodology, transformation results obtained using this model in a specific locality may differ from results provided by the transformation service or the Coordinate Transformation application of the ČÚZK Geoportal. To ensure a uniform transformation procedure and homogeneous results, it is recommended to use these applications or software tools approved by ČÚZK.