We use least squre method to form conicoid mathematic model and fit the point cloud which has been grouped by octree subpision method.

应用最小二乘法建立二次曲面的数学模型，对于已用八叉树分组的点云数据实现隐函数拟合。

One is the conic treatment method with fixed water-head, and the other one is conicoid treatment method with changing water-head.

即固定水头下的一元二次函数协联处理方法与可变水头下的二元二次曲面拟合处理方法。