Item Height

Datum:

Survey Datum ( Name )
Height value will be on the selected survey datum ellipsoid, e.g 'ED50'.
Note that Survey datum (or Horizontal Datum) is set in the Geodetic Configuration as Project Coordinate System.
2nd Datum ( Name )
Height value will be on the selected Source Coordinate System in the Geodetic Configuration, e.g. 'WGS 84', 'ITRF2008' or 'ETRS89'.
Chart Datum ( Name ) - Default
Height value on the selected vertical datum, e.g 'NAP - De Min Geoide'.
Note that Chart Datum (or Vertical Datum) is set in the Geodetic configuration as Vertical Datum under the Project Coordinate System.
Actual Water Level
Height value above the actual water (or sea) level.
The following formula is used: Geoid Level + Tide + Swell
The swell is derived from the roll, pitch and heave of the reference node, and the offset of the selected node to the reference node.
The heave value of the reference node can be monitored under the heave column of the Height Aiding driver.
Mean Water Level
Height value above 'mean' water (or sea) level.
The following formula is used: Geoid Model + Level Model + Offset
Geoid Model Level
Height value above input geoid model. Only used in case of River Height Model.