An official Brazilian delegation recently visited Deltares to discuss possibilities to better connect vertical reference systems covering both land and sea using accurate hydrodynamic modelling.
The delegation includes specialists from the Ministry of the Environment (MMA), from the Navy’s Hydrography Center (CHM), from the Army’s Geography Service (DSG), from the federal Geological Service (CPRM), from the Defense Ministry in Brasilia and from the federal Institute for Geography and Statistics (IBGE).
This visit was part of a 5-day program in the Netherlands, coordinated by Delft University of Technology.
Difficult to maintain good datasets
Brazil has a very long coastline of about 8500 km which makes it very difficult to maintain good datasets for coastal zone management.
Recently, a group of institutes together formed a task-force to collect the combined geographical data for the Brazilian coast and establish the reference systems needed to support this.
This task-force started in 2015 and the six people visiting Deltares are all members of this group.
Overall the task-force is thinking about using GPS (GNSS) and airborne gravimetry to create a geoid. In that approach a numerical model is needed to connect the sea level to the geoid.
The overall objective of the Brazilians is to make it possible to integrate depths and heights, or more specifically, data sets of which the vertical coordinate is given with respect to Chart Datum (e.g., bathymetry) and data sets of which the vertical coordinate is given with respect to the geoid (land topography).
As such, they need Chart Datum (ie a tidal datum) with respect to the geoid.
They are aiming for two pilot sites/regions to show what can be done and in the future establish and maintain these for the full coast.