Raag Pradhan - Types

Poorvang

• Lower regions of the primary octave (S-P)
• Generally sung post noon (deep and introspective)

Uttarang

• Upper registers of the primary octave (typically P-S')
• Most of these raags come alive in the morning

A raag being one of the types does not mean other parts of the Raag are ignored. Rather, as Ragopedia puts it

Expressive maneuvers and cadences are skillfully placed in the desired region as often as possible 

Six raags are considered fundamental : Bhairav, Malkauns, Hindol, Dipak, Megh and Shree

Janak raag - when the thaat is the raag itself.
Janya raag - derivatives of the janak raag or the rasa.