Unfortunately have tonne of geographical aid (5)
I believe the answer is:
atlas
'geographical aid' is the definition.
(I've seen this in another clue)
'unfortunately have tonne' is the wordplay.
'unfortunately' becomes 'alas' ('alas' is used to express regret).
'have' is an insertion indicator.
'tonne' becomes 't' (synonyms).
'alas' enclosing 't' is 'ATLAS'.
'of' acts as a link.
(Other definitions for atlas that I've seen before include "used for maps" , "Size of paper once" , "Collection of maps" , "Sky-toting Titan" , "Mythological Titan (involved with the world of maps?)" .)