This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
A continent entry records how classical chorography, the astrological geography Ptolemy sets out in the second book of the Tetrabiblos, assigns a region of the inhabited world to a zodiacal triplicity and a set of ruling planets, a documented ancient attempt to extend astrology's planetary and zodiacal categories from the individual chart to the character of whole peoples and places.
An entry records which quarter of Ptolemy's own fourfold division a continent falls in, which triplicity and planets that quarter is paired with, and states plainly where Ptolemy's own geographical knowledge simply did not extend, since his chorography maps only the inhabited world as the Hellenistic Mediterranean understood it and has nothing at all to say about regions, the Americas foremost among them, that lay entirely outside that horizon.
Robbins' critical edition, prepared for the Loeb Classical Library directly from the Greek text with a facing English translation, is the documented scholarly basis for reading Ptolemy's chorography accurately rather than through a later paraphrase, and an entry cites it for the specific quarter, triplicity and planetary assignment Ptolemy's own text gives, distinct from any later writer's extension or revision of that ancient scheme.