The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished o...The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished on railway four-electric majors′professional construction.According to the typical high-speed railway project construction′s technology,these four-electric professional construction′s technology scheme are made into construction method′s video,according to the technology plan′s characteristics of professional,visualization and information,under the premise of improving the efficiency about professional project management and construction of the railway four-electric project,the critical technology problems of railway four-electric project are solved.At the same time,it also improves efficiency of BIM model′s construction,the cooperation management′s efficiency of construction process,and the ability of integrating model information.展开更多
【目的】以人工落叶松为例,探索基于无人机激光雷达(Unmanned aerial vehicle LiDAR,UAVLiDAR)点云的单木探测提取树高的误差对胸径反演的影响并校准,实现单木参数(胸径、树高)的准确度量,为大尺度高效便捷估测单木参数提供新的思路。...【目的】以人工落叶松为例,探索基于无人机激光雷达(Unmanned aerial vehicle LiDAR,UAVLiDAR)点云的单木探测提取树高的误差对胸径反演的影响并校准,实现单木参数(胸径、树高)的准确度量,为大尺度高效便捷估测单木参数提供新的思路。【方法】以东北林业大学帽儿山实验林场13块4个龄组(幼龄林、中龄林、近熟林和成熟林)的落叶松人工林样地UAV-LiDAR数据及野外调查数据为数据源,基于UAVLiDAR点云的单木探测提取的树高,分别以普通最小二乘法(Ordinary least squares,OLS)和3种误差变量回归(标准主轴(Standard major axis,SMA)、远程主轴(Ranged major axis,RMA)和极大似然估计(Maximum likelihood estimate,MLE))构建胸径-树高模型,研究探测误差对各龄组人工落叶松胸径反演的影响并校准。【结果】利用UAV-LiDAR点云的单木探测提取4个龄组树高的相对均方根误差(rRMSE),误差范围为3.41%~5.14%;在胸径-树高模型预测方面,3种误差变量回归均优于OLS,RMA预测效果最好,4个龄组反演单木胸径的rRMSE降低了2.21%~3.58%。【结论】当满足模型假设时,误差变量回归比OLS在预测响应变量方面表现更好,是估计无偏的模型系数的理想方法,本研究中RMA方法表现最好;本研究所构建的人工落叶松胸径反演模型具有较高的预估精度,各项误差均保持在合理范围内,可实现应用UAV-LiDAR高效便捷地估测大尺度森林单木参数的目的,可在实践中推广。展开更多
文摘The visualization operation of railway four-electric engineering construction is an important part in railway′s construction,which plays a critical role in improving operation efficiency and it is smoothly finished on railway four-electric majors′professional construction.According to the typical high-speed railway project construction′s technology,these four-electric professional construction′s technology scheme are made into construction method′s video,according to the technology plan′s characteristics of professional,visualization and information,under the premise of improving the efficiency about professional project management and construction of the railway four-electric project,the critical technology problems of railway four-electric project are solved.At the same time,it also improves efficiency of BIM model′s construction,the cooperation management′s efficiency of construction process,and the ability of integrating model information.
文摘【目的】以人工落叶松为例,探索基于无人机激光雷达(Unmanned aerial vehicle LiDAR,UAVLiDAR)点云的单木探测提取树高的误差对胸径反演的影响并校准,实现单木参数(胸径、树高)的准确度量,为大尺度高效便捷估测单木参数提供新的思路。【方法】以东北林业大学帽儿山实验林场13块4个龄组(幼龄林、中龄林、近熟林和成熟林)的落叶松人工林样地UAV-LiDAR数据及野外调查数据为数据源,基于UAVLiDAR点云的单木探测提取的树高,分别以普通最小二乘法(Ordinary least squares,OLS)和3种误差变量回归(标准主轴(Standard major axis,SMA)、远程主轴(Ranged major axis,RMA)和极大似然估计(Maximum likelihood estimate,MLE))构建胸径-树高模型,研究探测误差对各龄组人工落叶松胸径反演的影响并校准。【结果】利用UAV-LiDAR点云的单木探测提取4个龄组树高的相对均方根误差(rRMSE),误差范围为3.41%~5.14%;在胸径-树高模型预测方面,3种误差变量回归均优于OLS,RMA预测效果最好,4个龄组反演单木胸径的rRMSE降低了2.21%~3.58%。【结论】当满足模型假设时,误差变量回归比OLS在预测响应变量方面表现更好,是估计无偏的模型系数的理想方法,本研究中RMA方法表现最好;本研究所构建的人工落叶松胸径反演模型具有较高的预估精度,各项误差均保持在合理范围内,可实现应用UAV-LiDAR高效便捷地估测大尺度森林单木参数的目的,可在实践中推广。