Project title: Improving the Quality of Height Data Transformation
Acronym: HRTrans
Vrsta i financiranje: institucionalni istraživački projekt, financiran iz sredstava Nacionalnog plana oporavka i otpornosti 2021. – 2026. (Izvor 581-mehanizam za oporavak i otpornost).
Implementation period: 1 October 2025 - 30 September 2029
Project Manager: Ivan Razumović
The introduction of new national reference coordinate systems creates the need to ensure continuity in the use of spatial data. The Croatian height transformation model HTMV is the basic and official infrastructure for the transformation of height data between the old HVRS1875 and the new HVRS71 height reference system of the Republic of Croatia. The Croatian height transformation model is integrated into the T7D, the official software for the unified transformation of positional and height coordinates of points in the territory of the Republic of Croatia, whose official use has been prescribed by the State Geodetic Administration of the Republic of Croatia. HTMV was realized as a grid transformation model based on separate modelling of datum and distortion components of height differences. The main objective of the project an independent analysis of external accuracy of the Croatian height transformation model in the territory of the Republic of Croatia and improvement of quality of the existing transformation model by implementing the concept of hierarchical decomposition of a homogeneous transformation grid into sub-grids with smaller cell sizes for particular local areas covered by the model that are adapted to the number and positional distribution of benchmarks in the area where they are located. The focus is on larger towns along the coast of the Republic of Croatia (Pula, Rijeka, Split, Dubrovnik), but also in the interior (Osijek) where there are larger city levelling networks with a large and adequately homogeneous benchmark field, for which areas an independent analysis of the quality of the HTMV does not exist.