Giclée on Heavy Cotton
850 x 140cm
“It is not down in any map; true places never are.”
– Herman Melville, Moby Dick
In 1884 Greenwich Mean Time (GMT) was established by international agreement as a world standard. It measures from the Greenwich Meridian that assigns zero degrees longitude, where east meets west.
It was arranged to the locally-orientated Principal Triangulation of Britain, undertaken from 1783 to 1853, a datum that used the Airy 1830 ellipsoid- a shape that approximates the form of the earth.
One hundred years later, the WGS84 (World Geodetic System 1984) was established for GPS positioning. Measured using atomic time, it was also adopted as an international convention. It is a three-dimensional coordinate system that uses the GRS80 (Geodetic Reference System 1980) ellipsoid, and is designed for positioning anywhere on the earth.
The GRS80 ellipsoid is somewhat bigger than the Airy ellipsoid and has a slightly different shape; both account for the equatorial bulge, and neither fits the Earth perfectly.