Accuracy of Easting Northing to Lat Lng

[stevegoddard]

With version 1, I could take an E/N, convert to Lat/Lng and plot on a Bing OS map with almost perfect accuarcy.

I have just moved to version 2 and points plotted appear to be 10-20m out. I'm plotting 1km grid squares which should line up perfectly with the blue OS grid lines (and did in version 1).

I.e.

Version 1.1.2

$var_grid_ref_osref = new OSRef($var_easting, $var_northing); 
$var_grid_ref_lat_lng = $var_grid_ref_osref->toLatLng();
$var_grid_ref_lat_lng->OSGB36ToWGS84();

"easting": ​322000, "northing": ​241000, "lat": ​52.06187, "lng": ​-3.13916

Version 2.0.1

$var_grid_ref_osref = new OSRef($var_easting, $var_northing);
$var_grid_ref_lat_lng = $var_grid_ref_osref->toLatLng();
$var_grid_ref_lat_lng->toWGS84();

"easting": ​322000, "northing": ​241000, "lat": ​52.06193, "lng": ​-3.13935

If I plot the points in ArcMap (without the toWGS84 conversion) they are perfect. So the issue seems to be with the toWGS84 function. To confirm this, I've checked and both version 1 and 2 return the same lat/lng values for this example if you take off the WGS84 conversion (52.06146,-3.13788). But after the OSGB36ToWGS84() in 1.2.1 or toWGS84() in 2.0.1 conversions I get different answers.

Is this an issue or am i doing something wrong?

Thanks
Steve

[dvdoug]

Hmm, interesting. I'll take a look at the weekend