Documentation
T2A API Documentation
GS 84 (GPS Co-ordinates)
We use the World Geodetic System standard co-ordinate system. Co-ordinates are expressed as signed decimal latitude and longitude values. This reference system is also use by the Global Positioning System (GPS).
OSGB36
The Ordnance Survey grid system projects Great Britain onto a 2D system comprising X and Y co-ordinates, in metres. The origin is at a point to the south west of Land's End. The X and Y co-ordinates are referred to as eastings (or east) and northings (or north) respectively.
Note that the OSGB36 grid system applies only to Great Britain and offshore islands - Northern Ireland and the Channel Islands are not included.
Irish Grid Reference System
The island of Ireland uses a similar system to OSGB36; co-ordinates are projected onto a 2D system which covers the island. This is independent from the GB system.
Examples
Great Britain
Here are the approximate positions of some GB places, in WGS 84 and OSGB36.
Name | Latitude | Longitude | X (Eastings) | Y (Northings) |
---|---|---|---|---|
London | 51.5 | -0.126236 | 530157 | 179576 |
Penzance | 50.118558 | -5.540874 | 30281 | 146977 |
Edinburgh | 55.944555 | -3.206062 | 324771 | 673047 |
Cardiff | 51.491848 | -3.194584 | 317161 | 177666 |
Leeds | 53.809035 | -1.546004 | 429993 | 424844 |
Aberdeen | 57.148134 | -2.121849 | 392726 | 806367 |
Norwich | 52.636641 | 1.288493 | 622611 | 309398 |
Northern Ireland
Here are the approximate positions of some places in Northern Ireland, in WGS 84 and the Irish Grid Reference System.
Name | Latitude | Longitude | X (Eastings) | Y (Northings) |
---|---|---|---|---|
Belfast | 54.5757 | -5.98257 | 142717 | 530157 |
Coleraine | 55.131994 | -6.668451 | 102550 | 591914 |
Ballymena | 54.863117 | -6.278343 | 125565 | 560426 |
Next: Data Sources
Documentation about the various co-ordinate systems used by the T2A API.