Re: GPS to grid reference

Bernard Hill wrote:


What's a "datum"? Is the L/Long not unique in converting to OSGB?

http://en.wikipedia.org/wiki/Datum

I'm not 100% up on the technical side but AIUI in layman's terms it's a way of measuring the Earth's shape. Lat/Long tends to use WGS84 datum whereas British National Grid uses the OSGB datum. Most GPS receivers come with Lat/Long as the default and automatically change the datum when you change to British National Grid. Others don't so you need to be careful. Once changed it'll stay that way unless you tell it otherwise.
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