Note on area identifying low points (6)
I believe the answer is:
minima
'low points' is the definition.
(I've seen this before)
'note on area' is the wordplay.
'note' becomes 'minim' (musical note).
'on' means one lot of letters go next to another.
'area' becomes 'a' (maths abbreviation).
'minim'+'a'='MINIMA'
'identifying' acts as a link.
(Other definitions for minima that I've seen before include "Least possible amounts" , "Lowest values" , "Least quantities" , "Lowest quantity or amount" , "bottoms" .)