Tolong jelaskan mengenai Geografi matematik dari Tanda Peninggalan Abad Lepas dalam bahasa melayu

Discussing the astrolabe, Al-Biruni considers the an orthographic cylindrical projection as his own invention, expanding upon the work of Al-Saghani.

Biruni was regarded as the most skilled when it came to mapping cities and measuring the distances between them, which he did for many cities in the Middle East and western Indian subcontinent. He often combined astronomical readings and mathematical equations, in order to develop methods of pin-pointing locations by recording degrees of latitude and longitude. He also developed similar techniques when it came to measuring the heights of mountains, depths of valleys, and expanse of the horizon, in The Chronology of the Ancient Nations.