Encode and decode British National Grid References

The Ordnance Survey encodes the coordinate of map tiles with names such as HU396753 (see the British National Gird page on Wikipedia).

This Python package has to encode and decode such references:

• decoding: given a tile name, get the coordinates of the tile in the EPSG 27700 coordinate system;
• encoding: given the coordinates of a point, get the name of the tiles that contain it;

Examples

To decode a tile name:

$ python -m os_grid_reference.ngr_decode HU396753 
{
    "sw_easting": 439600.0,
    "sw_northing": 1175300.0,
    "ne_easting": 439700.0,
    "ne_northing": 1175400.0,
    "size": 100.0
}

To find the 100m tile containing a point:

$ python -m os_grid_reference.ngr_encode --easting 439600.0 --northing 1175300.0 --size 100m
HU396753

See also

• a similar utility from Edina Digimap: NGConf
• a collection of Shapefiles representing the tiles: OSGB Grids