GISCO: Geographical Information and maps – Digital Elevation Model (DEM)

GISCO: Geographical Information and maps – Digital Elevation Model (DEM)

A ‘Digital Elevation Model (DEM)’ is a 3D approximation of the terrain’s surface created from elevation data.

The term ‘Digital Surface Model (DSM)’ represents the earth’s surface and includes all objects including e.g. forests, buildings.

The Digital Elevation Model over Europe from the GMES RDA project (EU-DEM) is a Digital Surface Model (DSM) representing the first surface as illuminated by the sensors. EU-DEM covers the 39 member and cooperating countries of EEA and it has been produced by a consortium led by Indra. Intermap edited the EU-DEM and AGI (Aerogeodezijos Institutas) provided the water mask. The EU-DEM dataset is a realisation of the Copernicus programme, managed by the European Commission, DG Enterprise and Industry. The EU-DEM is a 3D raster dataset with elevations captured at 1 arc second postings (2.78E-4 degrees) or about every 30 metre. It is a hybrid product based on SRTM and ASTER GDEM data fused by a weighted averaging approach. The EU-DEM has been generated as a contiguous dataset divided into 1 degree by 1 degree tiles corresponding to the SRTM naming convention. The spatial reference system is geographic, lat/lon with horizontal datum ETRS89, ellipsoid GRS80 and vertical datum EVRS2000 with geoid EGG08. The vertical unit of this DSM is metres. These tiles have then been aggregated into 5°x5° tiles which have been projected to ETRS-LAEA by JRC.

In addition, several products have been generated:

a) a colour shaded relief image over Europe has been created by EEA using a hillshade dataset derived from the ETRS89-LAEA version of EU-DEM (Please note that this dataset cannot be used for analysis purposes and that there are some known artefacts West of Norway.);

b) the hydrography layer (streams, confluence points, and watersheds) and

c) the Root Mean Square Error (denoting the error derived in the quality assessment procedure).

All datasets of Version 1 are made available as tiles (5×5° or 1000x1000km) and as single files:

•EU-DEM in ETRS89 (EPSG code 4258)
•EU-DEM in ETRS89-LAEA (EPSG code 3035)
•Colour shaded relief image over Europe in ETRS89-LAEA (EPSG code 3035)

The datasets are encoded as GeoTIFF with LZW compression (tiles) or DEFLATE compression (European mosaics as single files) for the raster files, and as GDB for the Vector data sets.

The EU-DEM statistical validation documents a relatively unbiased (-0.56 meters) overall vertical accuracy of 2.9 meters RMSE, which is fully within the contractual specification of 7m RMSE. The full report is found here.

European Environmental Agency’s metadata for EU DEM

Access the DEM datasets from here:

* EU DEM (ETRS1989)

EU DEM (LAEA)

* EU DEM Coloured relief

* EU DEM Hillshade

* EU DEM Aspect

* EU DEM Slope

* EU DEM RMS

* EU DEM Hydrography (ETRS1989)

* EU DEM Hydrography (LAEA)

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