[ncl-talk] utm2latlon function help

[Douglas Lowe]

Dear all,

I'm interested in converting from a northings-eastings grid to a lat-lon grid.
The original grid is for the UK - this is the information for the grid I have:
Projection    GREATBRITAIN_GRID
Datum         OGB
Spheroid      AIRY

I believe that the utm2latlon function might do what I need, but the 
help page for this function is not very descriptive for all the options needed:
https://www.ncl.ucar.edu/Document/Functions/Built-in/utm2latlon.shtml

In particular, it is not clear if the "grid_zone" attribute which is required 
supports the selection of the British National Grid zone, or if I would 
have to use 29U, 30U or 31U instead (and if so which of these I should 
pick).

Can anyone advise me on how to use this function?

Thanks,
Doug