Detail map, often (5)
I believe the answer is:
inset
'detail map often' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for inset that I've seen before include "Small picture inserted within a larger one" , "Picture inside a larger one" , "Extra page or piece added to enlarge" , "Training during term time for teachers in state schools" , "Page within a page" .)