Chords and Areas of Jambūdvīpa Regions in Jaina Cosmography
In Jaina works, the Jambūdvīpa (“Jambu Island”) is circular and of diameter \(D=100000\) yojanas (Tiloyapaṇṇattī \(=\) TP, IV. 11; Vol. II, p. 4; Kota, 1986). It is divided into 13 main regions by boundary lines which are all parallel to the east–west direction.