The Geodesy and Tides Department provides knowledge in these two fields, within the Hydrographic Office and elsewhere. Support is not limited to the Ministry of Defence. The geodetic expertise is often applied at sea, this is the so-called marine geodesy. In this respect, the sea level is often very important, which makes knowledge of tides necessary for marine geodesy.
The first application is positioning at sea, which involves the quality of navigation sensors, and the integration of those sensors in systems that perform a thorough quality check.
A second application is the establishment of correct coordinate systems, and the conversion between those systems. This concerns both the horizontal and the vertical references. Both are deduced from mathematical and physical models of the Earth's surface, or a part of it. Coordinate calculation always takes place within a reference system. The choice of the system greatly influences the calculation of positions, lines and areas. Examples are the determinations of boundaries according to the United Nations Convention on the Law of the Sea, maritime navigation, hydrographic measurements, and nautical cartography.
A third application concerns surveys at sea, and the subsequent statistical analysis of the large amounts of data that are collected. Modern depth measurement is a process in which many sensors are involved that all have their own specific error characteristics. This should be taken into account during the validation of the measurements, and during the analysis of sea floor behaviour in time. The latter is important for the determination of the survey frequencies for specific areas of the Netherlands Continental Shelf. Depth measurement is also referred to as bathymetry.
A fourth application is to support the production of nautical publications at the Netherlands Hydrographic Office. This concerns the publication of the predicted tides and currents, the conversion to the correct reference systems, referred to as geodetic datum for geographic coordinates, and the reduction level for depths.
The activities of the Hydrographic Office in the field of geodesy and tides are:
- to release products that are geodetically at a high level, and give a complete and correct overview of the horizontal and vertical tides.
- to collect bathymetric data compensating for the actual water level in the most appropriate way.
- to support the Ministry of Defence with information on geodesy and tides, in time and with high quality, given in an operational or in a policy environment.
- to advise other governmental organisations of the Kingdom of the Netherlands, including the overseas territories (Netherlands Antilles) on geodesy and tides.
- to develop, maintain and provide software on geodesy and tides, in support of public activities in this area.
- to provide information on geodesy and tides.
- to maintain good contacts with other organisations in the field of geodesy and tides, national as well as international.