Historical Chinese efforts to determine longitude at sea

TL;DR

Chinese maritime longitude determination methods, developed independently from European efforts, utilized astronomical observations and timekeeping, reflecting different societal needs but achieving comparable technical capabilities.

Contribution

This paper clarifies Chinese efforts in maritime longitude determination, highlighting their independence and technical parity with European methods despite different motivations.

Findings

Chinese navigators used astronomical and timekeeping methods at sea.

Chinese longitude techniques were independent and comparable to European methods.

Chinese efforts responded to administrative needs, not economic motivations.

Abstract

High-level Chinese cartographic developments predate European innovations by several centuries. Whereas European cartographic progress -- and in particular the search for a practical solution to the perennial "longitude problem" at sea -- was driven by persistent economic motivations, Chinese mapmaking efforts responded predominantly to administrative, cadastral and topographic needs. Nevertheless, contemporary Chinese scholars and navigators, to some extent aided by experienced Arab navigators and astronomers, developed independent means of longitude determination both on land and at sea, using a combination of astronomical observations and timekeeping devices that continued to operate adequately on pitching and rolling ships. Despite confusing and speculative accounts in the current literature and sometimes overt nationalistic rhetoric, Chinese technical capabilities applied to longitude determination at sea, while different in design from European advances owing to cultural and societal circumstances, were at least on a par with those of their European counterparts.