Nationwide Deformation Map shows (in)stability of The Netherlands

Bodemdalingskaart.nl, a SkyGeo product, is the successor of a joint effort in 2018 of NCG (Dutch Centre for Geodetics and Geo-informatics), SkyGeo and Technical University of Delft (TU). The launch of the new map this tuesday shows the movement of over 40 billion measurements throughout the country. While not so long ago these kind of data had to be gathered by manual levelling, the team now used Radar Satellite data (InSAR), thus ensuring bi-weekly re-measurement.

The dataset made public is much more detailed in contrast to the first release of the map back in 2018. Whereas in the first release satellite data was averaged to areas of 2 by 2 kilometer, the new detailed map shows every individual measurement, adding up to a staggering 40 billion measurement points in total.

The team of scientists and experts was hesitant in providing the data to the public at first. Although the measurements have a millimeter accuracy, interpreting or even diagnosing causes of differences in measurements requires a great deal of knowledge of (In-)SAR technology. Even so, the new release is of great public importance. According to Professor Ramon Hanssen of the TU Delft, some measurements can be an immediate call to action. Other measurements are harder to interpret, so findings should be investigated by InSAR experts first.

“We produced the map as part of our corporate responsibility to broaden knowledge around InSAR application. A major difference between the earlier version and the redesign of the National Deformation Map is it doesn’t show just ground displacement but you can also zoom into all kinds of objects like bridges, railroad tracks and even buildings’’, says Pieter Bas Leezenberg, CEO of SkyGeo, the company that processed the radar satellite data. Because of this feature, it assists municipalities and managers of civil infrastructure in maintenance planning.

Clearly visible is the displacement of levees and resonating heathlands. But also the water outlet of the nuclear plant at Borssele is subject to displacement. “In fact, analysis throughout the map shows the intense use of the surface”, says Hanssen. “This immediately requires us to be cautious in interpreting this data. What we see as colored dots on a map are actually a complex interaction between a satellite and objects on the surface of the earth. True interpretation requires expert knowledge.”

Even such, it is clear The Netherlands needs to invest tremendously in maintenance of infrastructure due to displacement and displacement soon. Roads, sewage systems, railroads and levees are impacted, but also industrial building complexes and individual buildings show signs of instability thus impacting governments, companies and house owners.

NCG, TU Delft and SkyGeo keep pursuing further development of the technology for continuous monitoring of objects and surface movement, as timely discovery of a hazardous situation might prevent calamities in the future.

The National Deformation Map viewer is available (in Dutch) at your request, do reach out to us to get your copy of the GIS dataset.