Os grid reference to lat long converter

While the conversion from geodetic to cartesian is straightforward, converting cartesian to geodetic is a complex problem. If you have more demanding requirements, you could compare e. Fukushima , Vermeille , Karney , and others. See documentation for full details. Distances between OS grid reference points are straightforward to calculate by pythagoras, once references are converted to numeric form.

See below for the JavaScript source code of the transverse Mercator projection and the datum transformation, also available on GitHub. Also to keep the scripts simple, I have included minimal error checking, and no user options for specifying precision.

I have also done a script for calculating distances between OS grid reference points. See below for the source code of the JavaScript implementation. These functions should be simple to translate into other languages if required.

This package turns given latitude and longitude coordinates into an 12 digit OS Grid Reference and vice versa. The coordinates may be given in decimal format or degrees, minutes and seconds. The following functions return an OSRef object which has the attributes easting and northing. Unless told otherwise, the package takes these Lat and Long coordinates as being in the WGS84 datum see below for custom datums.

If needs be, you can also call the getDegreeFromDecimal function to convert from decimal lat or long to degree - the function returns a 3 element array where the degree value is the 1st element, minutes are the 2nd and seconds are the 3rd. The following function returns a LatLong object which has the lat , long , height , and datum attributes.

The latitude and longitude that result from this function are returned in decimal form. See below to translate into degrees, minutes and seconds. It is possible to provide an OS Grid Reference in letter pair format e. TG rather than giving a separate easting and northing. Thanks so much for the help. I hope it wasn't too much hassle! Right I think i got it almost fully sorted! There is a little niggle in that the triginometry bit to figure out the distances between the input location in green and the wind farms aren't quite right, but i hope i shall be able to find out what it is and sort it by later on today.

I've attached the file so you can see what you have helped create and also in the hope you or someone else could see what is causing the distances to go wrong in the 'Reformatted Thanks again for your help T. Hey, Greenspan, I found the error. Look at equation C3 in the PDF. I changed the code and now the Northing comes out spot-on. Replace the code with this:.