German Niedersachsen Elevation Models

File:Niedersachsen-Coverage.png

Coverage of the DTM (DGM). Image credit: HVBG.

File:Niedersachsen-DGM.png

Niedersachsen Elevation Model (DGM)

Introduction

The digital elevation model for the German state of Niedersachsen (Lower Saxony) is derived from open geodata specific to this region. This data is generated through 3D airborne laser scanning, capturing a minimum of 4 points per square meter. The model is provided by the Landesamt für Geoinformation and Landesvermessung Niedersachsen (LGLN). Three versions of the elevation model are included with windPRO, each with different grid resolutions: 1m, 5m, and 20m. While the original model offer a maximum resolution of 1m, the two other models in windPRO are resampled by EMD to slightly coarser resolutions of 5m and 20m. This resampling is performed to ensure the data is better suitable for larger domains, which are typically required for wind farm analyses and wind flow modelling.

The 1m grid resolution data is specifically designed for photomontage modelling. Please note that the data provided by EMD reflects the status as of June 2024.

Dataset Overview

• Spatial Coverage: Bundesland of Niedersachsen (Lower Saxony)
• Resolution: 1m, 5m and 20m (in windPRO)
• Data-type: Digital Terrain Model (DTM)
• Coordinate system
  • Horizontal: ETRS89/UTM32 (EPSG 25832)
  • Vertical: EPSG 7837 (DHHN2016 mit Normalhöhen-Null (NHN))
• Version: Data were downloaded in June 2024. Data originates from years 2009-2020, dependent on area (see map to the right).
• Accuracy:
  • Vertical: For the 1m resolution dataset the vertical accuracy is stated to be ±0.15m for flat to slightly sloping terrain and ±0.30m for steep slopes with dense vegetation. For the 5m and 20m data we do not have any vertical accuracy records, but likely it is in the same magnitude as for the Hessen Data (±1.1m and ±5.1m respectively for 5m and 20m grid resolutions).
  • Horizontal: N/A
• No-data value: -9999 (in original source data)

Usage Notes

1. Please be aware that the download and processing time for the high-resolution datasets (1m and 5m grid) can take several minutes. This is due to the large volume of high-resolution elevation data and the tile-based storage system, which contains about 50,000 individual data-tiles. As such, downloading data for a specific site may take some time. If this poses an issue, consider downloading data for smaller areas or opting for the coarser 20m resolution data.
2. For the 1-meter grid, the downloadable area is restricted to a 5 km x 5 km region to maintain manageable file sizes. For the 5-meter grid, the downloadable area is limited to a 20 km x 20 km region. If necessary, the data within the elevation object can be supplemented with coarser data to cover a larger area. Please plan your downloads accordingly.

License and Attribution

The data is based on open geo-data of Niedersachsen, released under a open-data policy (CC-BY-40) on May 16th 2024.
When using the dataset, the please acknowledge the origin of the data, such as:

EMD/windPRO elevation model based on data from Landesamt für Geoinformation and Landesvermessung Niedersachsen (LGLN).

Acknowledgement

• The LGLN are thanked for producing this digital elevation dataset – and disseminating it in the public domain and thus for aiding the development of renewable energy and wind energy in particular.

External Links and Documentation

• Site with description of the elevation model (in German language) - HERE
• Coverage map (pdf) - HERE
• Information on open geodata in Hessen - HERE