The national deformation map shows the (in)stability of the Netherlands.
Leaning buildings, subsiding streets and dikes, and even drying nature reserves. Dutch citizens, municipalities, the government, and businesses will have to invest heavily in maintenance in the coming period. This is the result of the updated interactive national deformation map of the Netherlands.
Bodemdalingskaart.nl, a product of SkyGeo, is the result of a joint project from 2018 by the NCG (Netherlands Centre for Geodetic and Geo-information), SkyGeo, and Delft University of Technology (TU Delft). The launch of the new map last Tuesday shows the movement of more than 40 billion measurements across the country. Whereas this type of data had to be collected manually until recently, the team now uses radar satellite data (InSAR), enabling biweekly remeasurements.
The publicly released dataset is much more detailed than the first version of the map from 2018. Whereas the first version distributed satellite data over an average of 2 by 2 kilometers, the new, detailed map shows every individual measurement, amounting to no less than 40 billion measurement points in total.
The team of scientists and experts initially hesitated to make the data public. Although the measurements have an accuracy of millimeters, interpreting or even diagnosing the causes of differences in measurements requires extensive knowledge of (In-)SAR technology. Nevertheless, the new publication is of great public interest. According to Professor Ramon Hanssen of TU Delft, some measurements can lead to immediate action. Other measurements are more difficult to interpret, meaning the findings must first be investigated by InSAR experts.
“We created the map as part of our social responsibility to increase knowledge about InSAR applications. An important difference between the earlier version and the revised version of the National Deformation Map is that it not only shows ground displacement, but also allows you to zoom in on various objects such as bridges, railway lines, and even buildings,” said Pieter Bas Lezelenberg, CEO of SkyGeo, the company that processed the radar satellite data. Thanks to this feature, the map helps municipalities and civil infrastructure managers plan maintenance.
The shifting of dikes and the vibrations of heathlands are clearly visible. But the water outlet of the nuclear power plant in Borssele is also subject to shifting. "Analyses of the map show that the surface is being used intensively," says Hanssen. "This immediately requires us to be cautious with the interpretation of this data. What we see as colored dots on a map is, in reality, a complex interaction between a satellite and objects on the Earth's surface. A correct interpretation requires expertise."
Nevertheless, it is clear that the Netherlands must invest heavily in infrastructure maintenance in the short term due to the shifts and the resulting damage. Roads, sewers, railways, and dikes are affected, but industrial complexes and individual buildings also show signs of instability, with consequences for governments, businesses, and homeowners.
NCG, TU Delft, and SkyGeo continue to further develop the technology for continuous monitoring of objects and surface movements, because timely detection of dangerous situations can prevent disasters in the future.
The National Deformation Map viewer is available on request (in Dutch). Please contact us to receive your copy of the GIS dataset.
