3D measurement data NW

The 3D measurement data (3DM) from the laser scanning describe the terrain and the surface using irregularly distributed georeferenced elevation points. The average point density in NRW is 4 to 10 points per square meter. Especially in forest areas, the point density can increase significantly. Airborne laser scanning (ALS) is used as the detection method in North Rhine-Westphalia. The 3DM contain all reflections from the ALS in a classified measurement point cloud. The OGC standard LAS in version 1.2 in Point Data Record Format 1 (PDRF 1) is used as the data format. The data is provided in compressed LAS format (LAZ) via the download portal. In 2017, data acquisition was switched to so-called full wave laser scanning. Here, in addition to all reflections, additional information is recorded for each laser pulse. Since there has not yet been a comprehensive recording using full wave laser scanning, the data content and the number of point classes in NRW still differ. The WMS viewer "DHM overview" provides information about the availability and up-to-dateness of the 3D measurement data. Digital terrain models with a regular grid width are calculated from these raw data, the 3D measurement data. see DGM1), where the number in the designation indicates the grid width (ie a grid width of 1 m for DGM1).