The Shulbasutras of Baudhayana, Apastamba, Katyayana and Manava: With Text, English Translation and Commentary c8.t28.48

c8.t28.48

Let *E* and *W* be the eastern and western shadow points on the equinoctial day of the pole fixed at *O* (Fig. 1). Aptea suggests that the actual east-west line was determined by the shadow of the pole on the equinox day and verified by the rising and setting points of the star Kṛttikā. Then *EW* is in east-west or *prācī* line. Two knots are given at the two ends of a cord which is double of the original cord and are fastened at the poles at *E* and *W*. The cord is then stretched towards north by its middle point and a mark *N* is given at it. This is the north point. Similarly south point S is obtained. Then NS, gives the north-south line. In the *Śulbasūtras* the east-west line has always been drawn first presumably because of the importance attached to this direction.