基于DEM构造的空间网格曲面模型确定土方工程零线

Estimation of Earthworks Zero Line Based on Spatial Gridding Curved Surface Model Constructed by Digital Elevation Model

目的利用数字高程模型(digital elevation model,DEM)构造原始地形和场平设计地形的空间网格曲面模型,确定土方工程中的零线.方法通过实测提取原始地形DEM数据;依据空间直线方程,推导空间线段上任意点的坐标与方向余弦的数学关系式,采用Fortran90程序设计语言编写DEM数据提取程序,自动提取场平设计地形DEM数据;应用Surfer8.0和MapInfo软件构造规则的网格空间曲面模型并导出网格节点数据;擦除场平设计范围外数据.结果根据空间曲面交线上任意对应点的坐标x、y、z相等的性质,找出x、y、z数据相同的节点并连线,该线段即为土方工程的零线.应用此法尝试确定本山影视基地土方工程的零线,本法与方格网法比较,误差小于方网格法.结论用DEM构造的空间网格曲面模型可确定土方工程的零线,其零线的定位精度高于方网格法,该法为科学施工提供了更加准确的依据.

Earthworks zero line is determined by constructing the spatial gridding curved surface model of the original terrain and the field leveling design terrain by digital elevation mode （DEM）. The DEM data of original terrain are obtained by actual measurement. The mathematical correlation is deducted to demonstrate the relationship between the coordinates of any point on spatial line and the direction cosine by the spatial linear equation. DEM data obtaining program is compiled by Fortran90 and it is applied automatically to obtain the DEM data of field leveling design terrain. The standard gridding curved surface models are constructed by Surfer8.0 and Maplnfo and the gridding joints data are deducted. Then, the data out of the range of design scope are erased. Since the coordinates （：r, y z ）of any corresponding point on the spatial gridding curved surface are equal, the earthworks zero line is obtained by connecting two points with the same coordinates（x, y, z ）. The method mentioned above is applied to the estimation of earthworks zero llne of the project of t？,enshan Film and Television Base and it is found to be superior to the grids method in precision.