Results The difference values calculated were various with the arch form, the sequence was oval, round, parabola, catenuliform, and hyperbola from big difference to smell.

牙弓深度的差值按从大到小的顺序排列为：椭圆、圆、抛物、悬链、。

An equalarea pseudo cylindrical projection gather is constructed, in which the longitudes are hyperbola being symmetrical to the central meridian and the latitudes are parallel lines.

要构建了一个纬表象为平行于赤道的直，经表象为对称于中央直经的，且面积没有变的投影集合，并得到一组概括公式。