Kaiyuan from 12 years (AD 724), presided over large-scale delegation of the National Geodetic Astronomy, with Palace said, and others in Henan observation made by a group of the most successful.

• 从开元十二年（公元724年）起，一行主持大规模的全国天文大地测量，其中以南宫说等人在河南所作的一组观测最有成就。