Surya Siddhanta
याम्योत्तरदिशोर् मध्ये तिमिना पूर्वपश्चिमा । दिङ्मध्यमत्स्यैः सम्साध्या विदिशस् तद्वद् एव हि ॥
And thus, draw a line through the timi formed between the north and south points of the Meridian Line; this line will be the east and west line. In the same manner, determine the intermediate directions through the timis formed between the points of the determined directions (east, south &c.).
english translation
yAmyottaradizor madhye timinA pUrvapazcimA । diGmadhyamatsyaiH samsAdhyA vidizas tadvad eva hi ॥
hk transliteration by Sanscript