Map Projections of Northern Ireland 

Collection by Stefan A. Voser		 MapRef
MapRef
update19.March 1999

Map Projections
National Mapping Agency:
Ordnance Survey of Northern Ireland - OSNI
Reference Systems
  • Position: 
      • The Irish Grid (Ireland 1975): 
      Ellipsoid: Airy Modified
      Map Projection: Transverse Mercator
      Central Point/Datum: da-name
      Graticule Geographic (different)
      Ellipsoid: ell-name
      Datum: da-name
  • Height: 
      • Poolberg Datum (1837)
      Reference Point: Poolberg Lighthouse in Dublin Bay
      Reference Level: Poolberg Lighthouse on April 8.th, 1837
      Geoid: -
      Belfast Datum (1952)
      Reference Point: Tide Gauge at Clarendon Dock Belfast 
      Reference Level: Mean Sea Level (MSL) Belfast (Average 1951-56)
      Geoid: -
      Malin Head Datum (1957)
      Reference Point: Tidal Station at Malin Head in Co. Donegal
      Reference Level: Mean Sea Level Malin Head
      Geoid: -
Scale Mapping: 
Irish National Grid (1975)
Transvers Mercator
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© by Stefan A. Voser
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