GridFit函数，可用于原始场地地形地势复现、地形拟合及坐标点、高程数据提取。 gridfit函数，可用于原始地貌复现和地形数据的拟合与提取。代码说明详尽，编写简练。可实际应用，也可作为学习模板-gridfit functions for fitting and extraction of the original landscape and terrain data reproduction. Code Descr iption detailed, written and concise