3D mapping

3D mapping

The three-dimensional maps we produce offer insight into the shallow and deep subsurface. Our models are able to answer an increasing number of questions related to land use and the use of the deeper subsurface. In this way, the Geological Survey of the Netherlands (GDN) is helping stakeholders assess opportunities and risks and make decisions. 

Defining the subsurface in models

Three-dimensional maps make it possible to traverse the subsurface in all directions. In our models, we connect data obtained from boreholes and geothermal doublets, for example, as well as from borehole logs. We also acquire geophysical data ourselves through, for example, electromagnetic measurements. Using geostatistical techniques, we’re able to find the correlations hidden within these huge data sets. This allows us to predict what these diments between the data points look like. The more information we have, the more detailed the map. In this way, we’re also able to disclose the deep subsurface, for which relatively little data is available. Part of our 3D mapping is done within the framework of our statutory task of subsurface modelling.

Answer more questions in 3D

We work together with various stakeholder groups, who make their wishes known to us. The easy adjustability of 3D maps allows GDN to answer their questions about recent changes in the soil and subsurface, such as subsidence, its causes and consequences. Additionally, it is becoming easier to connect the land and sea, enabling our models to answer new questions about the use of the subsurface in coastal areas for the construction of wind farms, for example.

Working in 3D yourself

The subsurface can easily be viewed in 3D in your own GIS system or via your internet browser, thanks to the BRO 3D web services. There is also the SubsurfaceViewer: free professional software to view subsurface models in 3D on your own computer. As with the 3D web services, you can combine that with your own data. The SubsurfaceViewer and model files for use in the SubsurfaceViewer can be selected when downloading DGM, REGIS II, GeoTOP or DGMdeep through DINOloket or BROloket.

Cut-outs for specific purposes

Our models can be used to create cut-outs for specific purposes, such as the sandy gully systems of the Rhine and Maas rivers in the covering layer of South Holland, which was formed during the Holocene. The model subsequently shows at which locations and different depths continuous sand layers (‘channels’) surrounded by clay and peat occur, while also providing information about the grain size distribution of the sand. 

Top 50 metres in detail: GeoTOP

The GeoTOP model is especially used for issues related to infrastructure and the extraction of sand and gravel. GeoTOP provides a detailed three-dimensional image of the shallow subsurface, up to a depth of 50 metres below the Dutch Ordnance Datum (NAP). This is the part of the subsurface most intensively utilised by humans. GeoTOP is a refinement of the upper part of the moderately deep models, DGM and REGIS II. In GeoTOP, the Dutch subsurface has been divided into millions of voxels (a unit of volume) measuring 100 x 100 x 0.5 metres. Each voxel contains information about the type of soil and its associated physical and chemical properties.

NL3D is another (nationwide) model that offers a low-resolution alternative to GeoTOP with voxels measuring 250 x 250 x 1 metres. NL3D provides information about the soil profile up to a depth of 50 metres for the whole of the Netherlands.

Upper 500 metres: DGM and REGIS II

In het Digitaal Geologisch Model (DGM) is de ondergrond van Nederland opgebouwd van een diepte van 500 meter tot aan het maaiveld. In het model zijn de lithostratigrafische eenheden in de ondergrond digitaal op elkaar gestapeld. Het DGM geeft met dikte- en dieptevlakken inzicht in de opeenvolging van lagen, en verduidelijkt de ruimtelijke samenhang van de eenheden op regionale schaal in kaartbeelden en profielen.

Het REgionaal Geohydrologisch InformatieSysteem (REGIS II) is van belang voor provincies, waterschappen en waterleidingbedrijven. Het model is de hydrogeologische verfijning van het DGM en geeft inzicht in hoe doorlatend de bodem is voor grondwater. Elke geologische eenheid (formatie) is onderverdeeld in goed doorlatende (zandige) en slecht doorlatende (kleiige) lagen. De geohydrologische waarden in het model zijn gemiddelden voor toepassingen in grondwaterstudies. 

GeoTOP, DGM en REGIS II maken deel uit van de Wet op de Basisregistratie Ondergrond. Informatie over die modellen is te vinden via het BROloket.

Deep range: DGM-deep

Ons diepe model DGM Diep vormt de basis voor vragen over aardwarmte en is het framework voor informatie over conventionele energie. Het heeft een bereik tot, op sommige plekken in Nederland, 7.000 meter diepte. Het is van belang voor alle mijnbouwactiviteiten in ons land. Tot op heden was het van belang voor de gaswinning in Nederland. Tegenwoordig levert het ook een belangrijke bijdrage aan de energietransitie: het model kan helpen inschatten uit welke waterhoudende lagen – aquifers – aardwarmte te winnen is.

Knowledge for applications

Informatie die volgt uit onze kartering is ook te vinden via diverse tools die wij bieden. Zoals Delfstoffenonline, met kennis voor de winning van zand en grind. Op de website Grondwatertools, met daarop de Grondwaterstanden in beeld en de Grondwaterkwaliteit in beeld, bieden wij kennis waarmee een duurzame watervoorziening in te richten is voor burgers, industrie en landbouw.