Psion NGR to Latitude & Longtitude converter

NGRconv is a program for the Psion Series 3a, 3c or Siena which converts between UK National Grid References and latitude/longtitudes.

Download NGRconv now (only 6.5k)

It might work on the original Series 3, but I can't be certain. If you try it and it does, please let me know. If you try and it and it doesn't then I'll see what I can do to make it work if you ask nicely enough.

The conversion between NGR and latutude/longtitude can be done in either direction. If two locations are entered (grid or lat/long) then the distance and bearing between the two is also calculated.

Distance is quoted as the "Great Circle" distance, that is the distance around the circumference of the earth, rather than the direct path which is shorter due to the earth curvature.

Bearing is quoted as degrees "East of True North" which is NOT the same as Magnetic North or Grid North.

The program uses a different display according to the screen size available.

On the Psion 3a and Psion 3c it looks like this:

and on the Psion Siena it will look like this:


As far as I can tell the accuracy is pretty good, to within one figure (100 metres) when converting to NGR's and to within a second or two when converting to latitude/longtitude. The accuracy may be slightly worse than this around the fringes of the UK, perhaps 6 or 7 seconds of arc, but that's still pretty good.


NGRconv is distributed as Freeware. You may use it for a period of 14 days commencing the day of its first use, after which all users are required to register with the author.

Registration is FREE. Just send an email to: steve @ bramber .demon .co .uk, quoting your name and email address. All praise/comments/criticisms are welcome too.

This serves two purposes. Firstly it is so that I can keep registered users informed of any updates. Secondly it might encourage me to write some more Psion software.


NGRconv is copyright of the author, Steve Gutteridge.

No warranty is given on this program. No liability will be assumed for any injury, damage or loss to equipment, data or software or any incidental expenses incurred as a result of any such loss, damage or injury how so ever caused. You use this program at your own risk.

NGRconv must not be sold or altered but may be freely distributed provided that this copyright notice (included in the text file in the download) always accompanies it unaltered. NGRconv must not be used commercially without the author's permission, but otherwise permission is granted for free use of the program in any legal way which does not involve financial gain.

The executable file is distributed freely. The source code and the algorithms employed are not and are also the copyright of the author.

NGRconv may NOT be distributed on any Shareware collection disks or CD's which carry a cover price greater then 10 pounds sterling without the expression permission of the author. If there's one thing that really winds me up it is so-called Public Domain software companies piling loads of "Free" software onto a CD and selling it for 30 quid or more without first asking the author's permission (and at least offering them a free copy of the CD!)

Psion Series 3, Series 3a, and Psion Siena are trademarks of Psion PLC.

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