As one of frame data of national spatial data infrastructure , digital elevation model excels contour line . it can express continuous gurgitation of ground , and it can also carry out relevant mathematical analyses and imitation , so it is applied broadly in various fields at present <中文摘要> =数字高程模型dem是国家空间数据基础设施的框架数据之一，其弥补了等高线的不足，既能表示地面的连续起伏变化，又适合作相应的数学分析和模拟，现在已在各个领域得到了广泛的应用。
