For pratical use and scientific research, Belgium must know the value of continuous variations of the geomagnetic field.This is one case for magnetic declination: it is used to find the direction of north with the compass. This is done using the Magnetic Observatories of Dourbes and Manhay. A complete measure of geomagnetic vector is recorded every second.

In addition to the measurements done in an observatory, there are frequently measurements done on the field all over Belgium. Upon request, field measurements can be requested outside Belgium. Everything is reported  using the International System of Units (SI) and magnetic measurements are accomplished with a precision of 0.1nT for magnetic inductions and 0.001° for angles.

The magnetic non-polluted environment at Dourbes makes  it into the ideal place to test the amagnetism of  materiels that can be used in industrial or research products.

The Earth's magnetic field is calculated regularly and published in annual reports. These results are recorded in international databases and at the RMI. They are also available online in quasi real-time on the INTERMAGNET site.