WGS84 and OSGB

[botogol]

In the UK I normally like to keep my GPS set to OSGB, so it tallies with the OS Map that I would normally be carrying.

When I'm entering a cache location from geocaching.com I therefore reset my GPS to WGS84, enter the lat/long coordinates, and then set it back. It's a bit tedious - do other people do this?

But I also notice that geocaching.com gives a OS grid reference.. but one the one ocasion I used it, I found myself some distance away.... it didn't seem to tally...


Am I right in thinknig that geocaching.com is giving an OS Grid reference, using the the WGS84 Datum? But is that a meaninful concept? Surely an OS Grid reference only makes sense with the OSGB datum...


help please! :blink:

[John Stead]

If you use the GC.com OS reference you should also use the OSGB datum. There are some errors in conversion but the biggest one is the omission of a leading zero in the OS grid reference. If there are only 11 digits in the reference, adding the appropriate leading zero usually puts it nearly right.