Global Mapper v26.0

British Grid to/from Lat/Long Problem

KGJames
KGJames Global Mapper UserTrusted User
edited January 2009 in Bug Report
I have 2 generic ASCII data files containing exactly the same points in Lat/Long and British Grid (Eastings, Northings). When I load them both, the Lat/Long set is displaced 113 metres, 303 degrees from the Eastings/Northings set. That's at in the same local area, I haven't checked at the other end of the UK.

For both imports, I used the ETRS89 datum

I used the UK Ordnance Survey's approved converter to convert from Lat/Long. There's an on-line version at :-http://gps.ordnancesurvey.co.uk/convert.asp

The first point in my data set is at (55.25188889N, 4.678666667W) in Lat/Long, or (229838.277E, 598572.21N) on the British Grid

Comments

  • global_mapper
    global_mapper Administrator
    edited January 2009
    Typically British Grid values are referenced to the OSGB36 (Ordance Survey 1936) datum and not ETRS89. Try bringing in your easting/northing file with that datum instead and see if it lines up with the ETRS89 lat/lon points.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • KGJames
    KGJames Global Mapper User Trusted User
    edited January 2009
    Brilliant, thank you!

    Oh for a flat earth

    Ken James
  • kentman
    kentman Global Mapper User Trusted User
    edited January 2009
    I think that most OS stuff is now referenced to WGS84

Categories

In this Discussion