中文说明：用二次曲面拟合的方法生成DEM的matlab的M文件,附件包含三部分内容，第一获取数据getdata，第二生成格网gridy，第三生成plot3yDEM,经检测可以正常运算.
English Description：
The attachment contains three parts: the first part is to get the data GetData, the second part is to generate the grid gridy, and the third part is to generate the plot 3Y DEM