The European Edition of MapPoint DOES NOT support OS Grid co-ordinates. :x

Or at least it should, but they are plotted incorrectly, with a 120-200metre error.

This is because the Eastings and Northings are converted to Latitude and Longditude WITHOUT any adjustment for the curvature of the earth. Plus MapPoint uses the American elipsoid model (GRS80/ETRS89/WGS84) and the OS Grid is based on the Airy 1830 Elipsoid model.

To convert Eastings and Northings for MapPoint you need to convert them to lat/long but using the (incorrect) WGS84 elipsoid model, apply the OSTN97 conversion to allow for the OS Grid being flat :roll: and then you'll have something that comes close.

My problem is that (a) MapPoint should damn well work and (b) my calcs have an error of up to 5 metres which makes the points plotted next to useless.

If you are picking up a disabled person, the vehicle needs to be on the right side of the road. Five metres would put you on the opposite pavement. Naff.

__________________
Regards

Anthony Hunt ach@kl2.com
Senior Technical Specialist
Kappa Lambda Squared Limited www.kl2.com
Erskine House, 53 London Road, Maidstone, Kent. ME16 8JH
Tel: 01622 670095
Fax: 01622 200119

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