实现三维区域增长，函数形式，I为输入，sp为起始点，range为变化范围，与平均值相比-Three-dimensional regional growth, functional form, I for input, sp is the starting point, range of changes in the scope, compared with the average

通过逐点内插法由不规则数据点的高程求格网点的高程信息，利用加权平均，附上了已知数据。-Through a point-by-point interpolation grid points irregular data point elevation and elevation information using the weighted average, enclose the known data.

Using the area of the element to weighted average a value to each point on the triangular mesh