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：形、形、抛物形、悬链形、双曲形。

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.

摘要构建了一个纬表象于赤道的直，经表象对称于中央直经的双曲，且面积没有变形的投影集合，并得到一组概括公式。