Cesium: incorrect vertical model position

  • Possible reason:
    • Incorrect project coordinate system: The coordinate system of the dataset uses a distinct vertical coordinate system but this is missing in the coordinate system description passed to SURE
  • Problem description:
    • When specifying a geographic coordinate system like ETRS89 without any additional parameters the vertical coordinates are expected to be ellipsoidal heights.
    • If the heights are actually specified in a different coordinate system like DHHN92 this will lead to an incorrect model position on the Cesium globe. The model can be either sunken into the ground or floating above it. This issue is solved in SURE by Over-imposing heights on target ellipsoid see the page of Mesh Converter.
    • Compound coordinate systems containing a separate vertical coordinate system can be defined but SURE does not support these. However, if you specify the compound coordinate system correctly SURE will warn you about the problem before starting any processing.
  • Solution:
    • When running the SURE executable please export to .osgb and later use the mesh converter to convert to Cesium using the method described below.
    • When running the mesh texturing module or the mesh converter use the --cs_vertical_shift flag to specify the offset between the ellipsoidal height and your vertical coordinate system.
    • When running the module of mesh converter use the flag of --cesium_over_impose_heights_on_target_ellipsoid