Bṛhat Saṃhitā chapter 14, Kūrma Vibhāga, arranges terrestrial regions through the image of a tortoise. Meridian documents one Kṛttikā-start scheme: a centre followed by eight directions, with three nakṣatras assigned to each division.
This is a classical mundane geography with textual and regional variants, not an ACG line and not a claim that modern political borders reproduce the source.
The map must always name the chosen scheme. Interpretations should invite comparison with experience while keeping the historical layer distinct from astronomical line geometry.