On the Deflection of Verticals in Japan

Abstract

Using 166 data of the deflection of verticals in Japan observed during the period from 1884 to 1950, a spheroid that most closely fits to the geoid in Japan was determined; the equatorial length being longer by 363 meters as compared with Bessel's ellipsoid and the ellipticity being 297.33. The absolute deflection of the vertical at the standard datum, A zabu, Tokyo, was obtained as ξ0=+10."40 and η0= -7 ."87. When we solved the absolute deflection having the shape and size of the spheroidunchanged as that of Bessel's, Eo and η0 were obtained as +9."81 and -7."44 respectively. Using the residuals from this solution, inclination of the geoid in Japan relative to the spheroid was roughly estimated.