Country Specific – Denmark

Our Danish elevation model is based on the official Danish elevation model (also known as DHM) produced by the Agency for Data Supply and Infrastructure (SDFI). Since 2018, SDFI updates the elevation model in partial increments of about a fifth of the country every year. The model has a horizontal resolution of 0.4 m and was released for the first time in this resolution in 2015, improving upon the previous model from 2007, which had a resolution of 1.6 m. The model is available in SCALGO Live under the name Terrain (Terræn). There are a couple of different variants of the model available.

Terrain/Buildings (Terræn/Bygninger): This is the raw model enriched with building footprints from the national GeoDanmark data set. For each GeoDanmark building footprint, we've raised the elevation of the cells there are inside the buildings with 10 m, relative to the highest elevation value of the original terrain model.

Terrain/Buildings/Rain (Terræn/Bygninger/Regn) and Terrain/Buildings/Sea (Terræn/Bygninger/Hav): Both models are derived from the Terrain/Buildings model and include the set of hydrological corrections from GeoDanmark.

Terrain/Buildings/Rain includes the corrections made for modeling water flowing downstream on the terrain, e.g., water from rain events. Terrain/Buildings/Sea is targeted for modeling flooding from sea. The main difference between the two models is infrastructure like sluices, and whether they are open or closed.

Surface (Overflade): This is the Digital Surface Model (DSM) version of the DHM. In this model houses, vegetation etc. is preserved in the elevation model.

Sources: A source layer, showing the acquisition year of the data, is available by clicking the gear icon next to an elevation layer and selecting the "Source" ("Kilde") tab, and then "Show source information" ("Vis kildedata"). Use it to figure out how old the data is for your project area. You can use the point query tool to get the acquisition year for a particular area.

Terrain (2018-2022) (Terræn (2018-2022)):

This is a historical version of DHM, released in 2023 based on scans from 2018-2022.

Surface (2018-2022) (Overflade (2018-2022)):

This is the Digital Surface Model (DSM) version of DHM from 2018-2022.

Terrain (2015) (Terræn (2015)):

This is a historical version of DHM, released in 2015 based on scans from 2014-2015. It was the first model released by SDFI with a resolution of 0.4 m.

Surface (2015) (Overflade (2015)):

This is the Digital Surface Model (DSM) version of DHM from 2015.

Terrain (2007) (Terræn (2007)):

This is an older model of Denmark released in 2007 based on scans from 2005-2007. It has a horizontal resolution of 1.6 m.

Surface (2007) (Overflade (2007)):

This is the Digital Surface Model (DSM) version of DHM from 2007.

Terrain (QuickDHM) (Terræn (QuickDHM)):

This is a temporary version of DHM with the newest available data from SDFI. Is have not been quality checked and errors and missing data occurs. It has a horizontal resolution of 0.4 m.

Surface (QuickDHM) (Overflade (QuickDHM)):

This is the Digital Surface Model (DSM) version of QuickDHM.

Soil type (Jordtypekortet)

SCALGO Live includes a map of topsoil types in Denmark which is based on a national map of soil types, known as Jordtypekortet, from the Department of Agroecology at Aarhus University. Jordtypekortet classifies the soils of Denmark into types based on analyses of soil samples taken mainly from farmland, interpolated to cover the entire country. For more information on the orginial data, please read the information provided for the layer in the Library. For more information about how the topsoil map is produced and used in SCALGO Live, please see the soil type section.

Land Cover (Arealdække)

SCALGOs land cover map is available in Denmark. It is produced in 20cm resolution, based on the national orthophoto provided SDFI and a few auxiliary sources. For information on the data that went into the most recent land cover map, please read the information provided for the layer in the Library. For more information about how the land cover data is produced and used, please refer to the land cover documentation.

Infiltration and drainage to sewers

The Flash Flood Map supports the use of runoff functions to specify the runoff generated from each cell as a function of the rain depth. In Denmark we have produced a national Flash Flood Map where we use runoff functions to include infiltration and drainage to sewers in the model. When you enable infiltration and drainage in the Flash Flood Map, the infiltration at a cell is determined by the cell’s land cover class, as well as its soil type (in natural areas) and sewer map status (in artificial areas).

In artificial areas, if a cell is in an area that has any kind of sewer system, then we apply a CN-p-curve that represents the capacity of an average Danish sewer system. Other impervious areas use the glass model with no initial loss, i.e. all rainfall is turned into runoff.

In natural areas, dense vegetation areas are assumed to have loose soil, while shallow vegetation and bare land areas are assumed to have compacted soil. Each soil type in the topsoil map has a CN-p-curve for both compact and loose conditions.

For more information about the Flash Flood Map with infiltration and drainage, including information about parameter settings and CN-p-curve numbers, we refer to our in-depth white-paper.

To view the runoff functions used for individual soil types, click “View Runoff Functions” in the infiltration and drainage popup.

If you want to investigate the sewer type mapping and the soil type data used in the computation you can find them both in the library.

Rain events 

In the Core+ module DynamicFlood, SCALGO Live provides a selection of design rain events for use in the simulations. These rain events were created based on data and recommendations from the latest "skrift" and accompanying spreadsheet tool provided by Spildevandskomitteen.