基于MapGIS数字高程模型基岩面高程等值线图的制作

The Method of Drawing Bedrock Surface Contour Map by Using MapGIS

基岩面高程等值线图是建立三维地质模型所需的一项重要数据,也是三维地质调查工作的一项重要任务。制作基岩面高程等值线的主要数据源为钻孔和地形等高线。在制作过程中,首先对钻孔数据进行筛选和标准化处理,筛选出347个钻孔投影成Map GIS的点文件(.WT),为提高精度,使成图更符合实际情况,结合武汉市地形特征,提取地表基岩露头出露部分等高线(.WL)代表露头区基岩面高程。再利用Map GIS DTM分析数字高程模型对钻孔和等高线对应的点文件和线文件(.WT和.WL)剖分插值网格化,生成平面和立体的基岩面等值线图。通过对Map GIS提供的4种剖分插值结果进行对比分析,应用Kring泛克里格网格化模型绘制的基岩面高程等值线图更符合实际情况,同时也更快速、方便。需要注意的是,在使用Kring泛克里格网格化方法时,应对数据进行正态分布检验。

Bedrock surface contour map is one of the most important dates for 3D geological model ,and a important duties for 3D geo-logical survey also .Drawing bedrock surface contour map bases on boreholes and contour .Firstly, screen the useful boreholes and made them normalization .347 boreholes were screened to map in point file （ .WT）by projection transformation . For a more accurate and more reasonable map , selects the contour of the outcrop to join in the drawing , which represents bedrock surface contour there . And then, using DTM module of MapGIS, grids the discrete date and draws the contour map and 3D contour map.With comparison and analysis of 4 models in MapGIS , Kring model is the best one .It is worth noting;however , that normal distribution test of the date is necessary before griding in Kring model .