Cartographic detail one sent for correction (5)
I believe the answer is:
inset
'cartographic detail' is the definition.
(I've seen this in another clue)
'one sent for correction' is the wordplay.
'one' becomes 'i' (Roman numeral).
'for correction' indicates an anagram (I've seen this in other clues).
'sent' is an anagram of 'nset'.
'i'+'nset'='INSET'
(Other definitions for inset that I've seen before include "Thing inserted" , "Small picture inserted within a larger one" , "Page within a page" , "Small diagram contained by larger one" , "Extra page or piece added to enlarge" .)