一、旋转椭球体又称地球椭球体或旋转扁球体，是地球经线圈绕地轴旋转而成。它是一个两轴椭球体，它的半长轴即地球赤道半径为６３７８．１千米，半短轴即球心距极点的半径（即极半径）为６３５６．８千米，半长轴比半短轴长２１．３千米，扁平率为１／２９８，形状为两极... 1. The spheroid is also called the earth ellipsoid or the spheroid. It is formed by rotating the earth around the axis of the coil. It is a two-axis ellipsoid whose semi-major axis is the radius of the Earth’s equator of 6378.1 kilometers. The radius of the semi-minor axis, that is, the radius of the center of the sphere from the pole (that is, the radius of the pole) is 6356.8 kilometers. The semi-major axis ratio The semi-minor axis is 21.3 kilometers long, the flat rate is 1/298, and the shape is two poles...