摘要
目前基于激光雷达(LiDAR)数据分析陆地重力近区、中区地形改正方法及其影响因素的文献较少。以往有关地形改正方法的精度评价都是基于某一个数学模型的假设条件,只能讨论高程测量误差对地形改正的影响,不能分析由扇形锥、扇形柱等数学模型产生的误差。为此,采用美国地调局三维高程计划(3DEP)的1 m×1 m间距LiDAR高程数据,选择12个数据区作为研究对象,以直棱柱模型重力解析式计算结果为地形改正参考值,从统计角度对比以往近区和中区地形改正数学模型与计算方法的精度——主要创新点;在此基础上,分析不同计算方法、不同地形网格间距的差异,并且对比不同方法的计算效率。结果表明:①近区地形改正范围与计算模型是影响近区地形改正计算的主要因素。混合模型方案可有效降低计算误差,当近区地形改正半径为20 m时,采用方案Ⅴ可以保证K区以外的11个区的平均相对误差小于20%;当近区地形改正半径为50 m时,采用方案Ⅶ可以将全区的平均相对误差控制在13%以内,是计算精度最高的方案。②地形起伏较平缓的丘陵(K区)的差异最大值与中山(J区)相当;在复杂地表的露天铜矿(L区),7种计算方案的差异最大值处于相同量级。③补角地形改正的修正公式不适用于丘陵,区域重力调查规范中的内接口补角地形改正的简化公式的适用性更强。④影响中区地形改正计算结果的因素包括高程数据网格间距、中区地形改正范围和计算方法,其中网格间距是主要因素。⑤综合计算精度和计算时间两个因素,质量线模型法为中区地形改正的首选计算方法。
There are few references on terrestrial gravity near⁃and medium⁃zone terrains correction and their influencing factors based on LiDAR data systems.Previous accuracy evaluation related to terrain correction methods is based on the assumption of a mathematical model,and it can only discuss the influence of the elevation measurement errors on terrain correction and fails to analyze the errors generated by mathematical models such as a sectorial cone or sectorial cylinder.To this end,this paper employs the 1 m×1 m LiDAR elevation data from the U.S.Geological Survey three⁃dimensional elevation program(3DEP)and selects 12 data areas as research objects.Meanwhile,it adopts the calculation results of gravity analytical formulas of the rectangular prism model as the reference value of terrain correction and statistically compares the accuracy of previous mathematical models and calculation methods for near⁃and medium⁃zone terrain correction,which is the main innovation of this paper.On this basis,this paper analyzes the differences in the calculation methods and grid spacing in various terrains and compares the calculation efficiency of different methods.The results are as follows.①The correction range of the near⁃zone terrain and the computation model are the main factors affecting the calculation results,and the hybrid model can re⁃duce the calculation error.When the correction radius of the near⁃zone terrain is 20 m,Scheme V can ensure that the average relative error of the 11 zones except the K zone is less than 20%.When the correction radius is 50 m,scheme VII can control the average relative error of all the zones below 13%,which indicates the highest calculation accuracy.②The maximum difference in the hill area with gently undulating terrain(Zone K)is comparable to that in the middle mountain(Zone J),and in the open pit copper mine zone with complex terrain(Zone L),the order of magnitude of the maximum difference for the seven schemes is nearly the same.③The correction formula for com⁃pensa
作者
邱隆君
孙诚业
杨亚斌
吴新刚
QIU Longjun;SUN Chengye;YANG Yabin;WU Xingang(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang,Hebei 065000,China;National Center for Geological Exploration Technology,Langfang,Hebei 065000,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2023年第5期1255-1268,共14页
Oil Geophysical Prospecting
基金
中国地质科学院物化探所基本科研项目(现代地质勘查工程技术集成与创新)
中国地质调查局项目“柴达木盆地盐湖区物探综合调查”(DD20230298)联合资助
关键词
LIDAR
数字高程模型
地形改正
网格间距
计算方法
计算精度
LiDAR⁃derived digital elevation model
terrain correction
grid spacing
calculation method
calculation accuracy
