Inoh Tadataka's Land-survey Expeditions in Japan and His Astronomical Observations

Abstract

 Land-survey expeditions across the Japanese archipelago during the period from 1800 to 1817 and scientific map-making conducted by Inoh Tadataka were monumental achievements in the Japanese history of cartography. How Inoh's astronomical knowledge and skills are reflected in his survey instrumentation and map fabrication of the Japan islands is reviewed. The contents of this paper are as follows: Section II makes an overview of Inoh's astronomical background nurtured both in his early life and at the Asakusa shogunal astronomical office; Sections III and IV discuss the influence of imported Chinese and Dutch books and European astronomical instruments on the survey apparatus used in the above expeditions; Section V describes his concrete star observation methods for determining local latitude, which were drawn by a local painter in the Kure district of Hiroshima in 1806; Section VI introduces survey work and map-making of the Sanuki fief in Shikoku by Kume Michikata, a surveyor and contemporary of Inoh, in contrast to those adopted by Inoh; and, Section VII comments on Inoh's cartographic policy and techniques in completing his famous Dainihon Enkai Yochi Zenzu (The Great Coastal Map of Japan).