It's right on the map (4)
I believe the answer is:
east
'it's right on the map' is the definition.
(I've seen this in another clue)
'on the map' is the wordplay.
'on' means one lot of letters go next to another.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'map' becomes 'eas' (I can't justify this - if you can you should believe this answer much more).
't' after 'eas' is 'EAST'.
Can you help me to learn more?
(Other definitions for east that I've seen before include "One regularly holding hands" , "Direction of the rising sun" , "Tom's friend" , "Airport near Derby" , "Sunrise direction" .)