This simple(!) library converts from WSG84 latitude and longitude values, as usually returned by GPS receivers, to OSGB36 values as used by the Great Britain Ordnance Survey and printed on OS maps, and then on to OS National Grid map references. The reverse process is also supported. For those who don't know the OS is Great Britains national mapping and survey service and is the primary source of map data for the UK. Ordnance Survey, Britain's national mapping agency Help is in the demo and source is included for merging. Runs under .NET 1.0/1.1 or later on device and desktop. EDIT :- Version 1.2 posted. ODN height added and more help in the demo. See post #4 below.