1. VORF, Bringing Land and Sea Together
Datums are an essential component of any SDI/MSDI.
Vertical Offshore Reference Frame, 2005
Joint Project with University College London (UCL)
Delivers seamless gridded vertical separation data to allow land and sea data to be joined and integrated.
Horizontal Data to WGS84 is complete
VORF methodology:
Satellite altimetry in open ocean
OSGM05 geoid model (UK)
Tide Gauge data for UK
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2. Methodology Satellite altimetry Tide gauge data Tidal modelling
GNSS observations
Plus gravimetric geoid, OSGM02 datum correction model, UKHO meta-data, coastline polygons, river polygons, etc.

3. Integration of datums – UK & Ireland
Heights with respect to ETRF89 datum across UK and Irish waters
Heights of all land datums in the British Isles, within the coastal zone – 17 of them.
Heights of Chart Datum, LAT, MLWS, MSL, MHWS, HAT (All used in marine charting). Unifies heights, elevations and depths.

4. Copyright © 2016 Open Geospatial Consortium
The Way Forward
Many Coastal states have developed their own VORF-like solutions
Harmonisation between member states
Updating – new geoid, better tidal measurements, better altimetry.
Distribution and use methodologies.
Copyright © 2016 Open Geospatial Consortium