Please can someone post a SQL function to convert easting/northing to longitude/latitude. I know it\'s incredibly complicated but I haven\'t found anyone who has documented it i
If anyone's interested in non-SQL solution I strongly recommend using this http://www.howtocreate.co.uk/php/gridref.php PHP/JavaScript class.
One important thing to mention here is the library supports Helmert transformation.
PHP
$grutoolbox = Grid_Ref_Utils::toolbox();
$source_coords = Array(54.607720,-6.411990);
//get the ellipsoids that will be used
$Airy_1830 = $grutoolbox->get_ellipsoid('Airy_1830');
$WGS84 = $grutoolbox->get_ellipsoid('WGS84');
$Airy_1830_mod = $grutoolbox->get_ellipsoid('Airy_1830_mod');
//get the transform parameters that will be used
$UK_to_GPS = $grutoolbox->get_transformation('OSGB36_to_WGS84');
$GPS_to_Ireland = $grutoolbox->get_transformation('WGS84_to_Ireland65');
//convert to GPS coordinates
$gps_coords = $grutoolbox->Helmert_transform($source_coords,$Airy_1830,$UK_to_GPS,$WGS84);
//convert to destination coordinates
print $grutoolbox->Helmert_transform($source_coords,$WGS84,$GPS_to_Ireland,$Airy_1830_mod,$grutoolbox->HTML);
JavaScript
var grutoolbox = gridRefUtilsToolbox();
var sourceCoords = [54.607720,-6.411990];
//get the ellipsoids that will be used
var Airy1830 = grutoolbox.getEllipsoid('Airy_1830');
var WGS84 = grutoolbox.getEllipsoid('WGS84');
var Airy1830Mod = grutoolbox.getEllipsoid('Airy_1830_mod');
//get the transform parameters that will be used
var UKToGPS = grutoolbox.getTransformation('OSGB36_to_WGS84');
var GPSToIreland = grutoolbox.getTransformation('WGS84_to_Ireland65');
//convert to GPS coordinates
var gpsCoords = grutoolbox.HelmertTransform(sourceCoords,Airy1830,UKToGPS,WGS84);
//convert to destination coordinates
element.innerHTML = grutoolbox.HelmertTransform(sourceCoords,WGS84,GPSToIreland,Airy1830Mod,grutoolbox.HTML);