Data Capturing of Latitude Observations in the Map Compilation Process of Ino Tadataka

Abstract

Ino Tadataka obtained coordinates (x, y) at latitude observation points through ground traverse surveys. In that process, he chose only the Y coordinate, which was derived from observed latitude using the meridian arc length of stars. As he could not observe longitude, he had to estimate the X coordinate as xY/y. Thereafter, he distributed the error of closure, that is, the differences between X and x or Y and y to traverse lines in ground surveys using a graphical method.