Importing Georeferenced data (DEMs, Point Clouds, ...) and computing TMs, STMs, 3SMs in Georeferenced DGNs - ISSUE and WORKAROUND

There is an issue affecting referencing/importing georeferenced data (Point Clouds, Digital Elevation Models in any format).

If the source data and the DGN file have a coordinate system (it may be the same) then elevations will be wrong.
Depending on the data/use case, the offset may be large or less detectable.

Affected datasources:

• all DEMs (HGTs, ASCs, Raster TIff  (SRTM as an example)
• all Point Clouds (LiDARs as an example)

Affected commands:

• Reference point cloud
• Compute Terrain model from Point Cloud
• STM  creation
• 3SM  (Terrain 3SM) creation

Affected versions: all

Workaround:

The Coordinate System has to be removed from data before import.

• For point cloud:
  Load the georeferenced pointCloud
  Remove GCS from Point Cloud (Utility > Remove GCS)
  Export Point Cloud and use this stripped file
• For DEMs:
  the GCS has to be stripped, one solution is to use QGIS to do so.
  workaround is detailed here for a HGT file, but this will work for ASC, GeoTIFF, ...

If you encounter this issue, please log a Service Request to raise the issue priority.

Best Regards