[poschiavanus]

See I completely missed the point of this (although I hope the link to co-ordinate translation is useful). Personally once things get like this I usually switch off: so congrats for Hedge Witch for seeing things straight off. My only comment is that there are a pretty small number of signs and as others have said they convert one to one to a symbol (letter or number). Therefore the range of solutions is not huge!

If this is geocacheing its too complicated for me! Certainly won't be applying to GCHQ for a job.

Having looked at it again I'd agree completely with Hedge Witch. Reuse symbols for A-I for 1-9, or just possibly A-J for 0-9. Usually mirror symbols are adjacent in the sequence. This gives two most likely candidates.