The model was created using a regularly-spaced grid with the resolution of 50 meters. The horizontal datum of the model is ETRS89. The vertical datum is a combination of Mean Low Water Spring (MLWS), Lowest Astronomical Tide (LAT) and Dansk Vertikal Reference 1990 (DVR90). The extent of the model is constrained between the Danish EEZ and the coastline, generalized at 1:100,000 scale.
The selection of the depths is based on a priority mechanism so that data from modern datasets are preferred to historical sources (e.g., multibeam survey vs. leadline). Then, the representative average depth is obtained by averaging all depths allocated from the selected input source to a given grid cell. When there is a lack of available bathymetric data, a depth estimate is provided using interpolation.
As such, the model depths are estimated using an averaging and interpolating approach, thus not targeted for safety of navigation. The original bathymetric datasets themselves are not distributed with the model, but described in the auxiliary layers to provide information about the bathymetric sources used for DDM.
The model is made available through the Danish data and map supply
The Depth Model can be downloaded as GeoTIFF files in the Lambert Conformal Conic (LCC) / ETRS89 projection (EPSG:3034). The model is also made available as an Open Geospatial Consortium (OGC) Web Map
The model consists of three layers
- ddm_50m.dybde The primary layer containing the depth values (in meters)
- ddm_50m.kilde An auxiliary layer providing the source of the depth data for each grid cell. The layer uses the following convention:
||The source is a digitalized survey fairsheet
||The source depths were collected using singlebeam echosounder
||The source depths were collected using a multibeam echosounder
||The depth values comes from a historical dataset (e.g., leadline)
||No source depths available, thus interpolation was applied
- ddm_50m.aar An auxiliary layer providing the year at which the data collection has ended (only for DIGI, SB and MB datasets).
A visualisation of the Depth Model in the form of a shadow-map, which gives a 3D expression of the seabed, is also provided as WMS. The depths are exaggerated to clarify the shapes of the terrain and amplify the 3D effect.
Terms and Conditions
The Danish Geodata Agency holds the copyright to Denmark's Depth Model.
See the Terms and Conditions for use here.