Updating of information on the Water Network of the Hydrographic Institute

In order to ensure the quality of the data collected by the tidegraphs belonging to the Maregraphic Network of the Hydrographic Institute, the Hydrographic Brigade held geometric leveling during the month of April in Lisbon and during the month of May in Aveiro, Douro (Cantareira), Leixões and Funchal.
During July the Hydrographic Brigade is performing geometrical levelings in Troy and Sesimbra.

The levelling works have as starting points the leveling marks of the High Precision Geometric Leveling Network (RNGAP).

At the same time, using the information available from the National Permanent Stations Network (RENEP) and the reference stations of the Hydrographic Institute and using the Global Navigation Satellite System (GNSS) observations, the positions of the levelling marks that serve as the basis of the observations of the tidegraphs were observed.

This additional work will enable the feasibility of using this methodology to the detriment of traditional observations by much longer geometric leveling.