15:30 〜 16:30
[G01-P-12] On adopting a realization of the EVRS as the national height system in mainland Portugal
The datum of the current national height system in mainland Portugal is based on the mean sea level at the Cascais tide gauge for the period between 1882 and 1938. The levelling network consists of measurements performed during several decades. Its last adjustment was done in 2000 using all the observations from different epochs. The fixed point for the adjustment was the geopotential number of the tide gauge reference benchmark at Cascais. Orthometric heights are used.
For practical reasons, like the use in pan-European applications as instructed by the INSPIRE directive of the European Commission, it would be very useful to have a national height system referring to the European Vertical Reference System (EVRS). At present however the EVRS is only accessible at the nodal benchmarks of the network that belong to the EVRF2007 network.
At the same time we need a more homogeneous and consistent levelling network. We will present the preliminary studies for the establishment in mainland Portugal of a new national realization of the EVRS, based on old and also a limited number of new precise measurements. We will discuss the possible strategies and their implications, considering the needs of the main users and the optimization of the available financial and technical resources. DGT, the Portuguese Directorate-General for Territorial Development, is the national authority for Geodesy and has under its responsibility the definition and maintenance of the Portuguese geodetic reference systems and frames including the height system.
For practical reasons, like the use in pan-European applications as instructed by the INSPIRE directive of the European Commission, it would be very useful to have a national height system referring to the European Vertical Reference System (EVRS). At present however the EVRS is only accessible at the nodal benchmarks of the network that belong to the EVRF2007 network.
At the same time we need a more homogeneous and consistent levelling network. We will present the preliminary studies for the establishment in mainland Portugal of a new national realization of the EVRS, based on old and also a limited number of new precise measurements. We will discuss the possible strategies and their implications, considering the needs of the main users and the optimization of the available financial and technical resources. DGT, the Portuguese Directorate-General for Territorial Development, is the national authority for Geodesy and has under its responsibility the definition and maintenance of the Portuguese geodetic reference systems and frames including the height system.