metre
EPSG
"The Irish Grid - A Description of the Co-ordinate Reference System" published by Ordnance Survey of Ireland, Dublin and Ordnance Survey of Northern Ireland, Belfast.
2003-06-27
OSGB Airy 1830 figure (ellipsoid code 7001) rescaled by 0.999965 to best fit the scale of the 19th century primary triangulation of Ireland.
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "Ellipsoid", "name": "Airy Modified 1849", "semi_major_axis": 6377340.189, "inverse_flattening": 299.3249646, "id": { "authority": "EPSG", "code": 7002 } }