Aerial Photography
Each spring, the Danish Agency for Climate Data collects aerial photographs of all of Denmark. The data is gathered in springtime to take advantage of optimal conditions – favourable flying weather and clear ground visibility before trees and bushes leaf out.
The photography is carried out in collaboration with the country’s municipalities through the GeoDanmark cooperation. Aerial photographs are used to produce GeoDanmark’s various map products and orthophotos. Both map products and orthophotos are published via The Danish Data Distribution Platform and The Danish Map Supply as open data.
The Danish Agency for Climate Data has been responsible for capturing aerial photographs for many years and therefore has an extensive collection with yearly updates, dating back many years.
Since 2008, the Agency, in collaboration with other public partners, has also collected aerial photographs in the summer for the production of summer orthophotos. The finished summer orthophotos are used as a basis for administration, presentations, and planning by these partners.
Orthophotos
Orthophotos are aerial photographs that have been “rectified” to be geometrically accurate. They are also colour- and contrast-adjusted to give the impression of a single photograph of all of Denmark.
The quality of orthophotos plays a crucial role for public authorities when working with roads, buildings, streams, etc. Therefore, it is important to be able to measure distances accurately, just as you can on a map with a fixed scale.
The Danish Agency for Climate Data annually updates orthophotos according to GeoDanmark’s current specifications.
LiDAR Scanning
Each year, The Danish Agency for Climate Data also performs LiDAR scanning of the Danish landscape. The collected data is used to produce the Danish Elevation Model.
LiDAR scanning is performed by measuring distance and direction to the ground from a laser distance meter on an aircraft. Knowing the aircraft’s position and orientation allows the precise location where the laser hits the ground to be calculated. This collection of 3D points forms the so-called “point cloud”, which is the basis for both terrain models and surface models.
After data collection, extensive work is performed to correct for errors in the data (e.g. reflections from birds). The finished data has an accuracy in height that varies from a few centimetres to around half a meter, depending on the surface.