Matsya Purana — Solar–Lunar Motions
तस्याश्चार्धप्रमाणं च मेरोश्चैवोत्तरोत्तरम् मेरोर्मध्ये प्रतिदिशं कोटिरेका तु सा स्मृता //
tasyāścārdhapramāṇaṃ ca meroścaivottarottaram merormadhye pratidiśaṃ koṭirekā tu sā smṛtā //
And its measure is taken as a half; and likewise, with Mount Meru, the measure increases successively toward the north. In the middle of Meru, in each direction, that line is remembered as extending by an extra koṭi.
This verse is not about Pralaya; it belongs to the cosmographic mapping of the world-system, describing how measures around Mount Meru are reckoned (half-measures and progressive northern increase).
Directly, it does not prescribe royal or household duties; indirectly, such cosmography frames the Purana’s sacred worldview that supports dharma by situating rituals, pilgrimages, and sacred geography within an ordered cosmos.
Architecturally it is not a Vastu rule, but the idea of directional measurement (prati-diśam) and a central axis (meror madhye) echoes the sacred ‘center-and-directions’ logic used in temple orientation and ritual space-planning.