As a GIS tool,visibility analysis is used in many areas to evaluate both visible and non-visible places.Visibility analysis builds on a digital surface model describing the terrain morphology,including the position an...As a GIS tool,visibility analysis is used in many areas to evaluate both visible and non-visible places.Visibility analysis builds on a digital surface model describing the terrain morphology,including the position and shapes of all objects that can sometimes act as visibility barriers.However,some barriers,for example vegetation,may be permeable to a certain degree.Despite extensive research and use of visibility analysis in different areas,standard GIS tools do not take permeability into account.This article presents a new method to calculate visibility through partly permeable obstacles.The method is based on a quasi-Monte Carlo simulation with 100 iterations of visibility calculation.Each iteration result represents 1%of vegetation permeability,which can thus range from 1%to 100%visibility behind vegetation obstacles.The main advantage of the method is greater accuracy of visibility results and easy implementation on any GIS software.The incorporation of the proposed method in GIS software would facilitate work in many fields,such as architecture,archaeology,radio communication,and the military.展开更多
为探究精细化机载点云数据在大比例尺地形图测绘中的应用效益,提高基于机载点云数据绘制数字地形图的精度,选取了建模难度较大的带状地形作为测区,并获取了点云模型。使用Li DAR 360软件对点云数据进行精细化预处理,提高了点云模型的地...为探究精细化机载点云数据在大比例尺地形图测绘中的应用效益,提高基于机载点云数据绘制数字地形图的精度,选取了建模难度较大的带状地形作为测区,并获取了点云模型。使用Li DAR 360软件对点云数据进行精细化预处理,提高了点云模型的地面拟合度。结合点云模型与三维实景模型绘制1∶500的大比例尺地形图,并根据GPS-RTK获取的100个校核点对地形图精度进行了分析。研究结果表明:采用模型质量和测绘专项需求精细化处理方法可提高点云模型的地面拟合度,且绘制的地形图满足1∶500大比例尺地形图的绘制要求。展开更多
[目的]研究基于梯田DEM的地形湿度指数,为深化黄土高原地区土壤水分的研究提供依据。[方法]以黄土高原地区梯田为研究对象,选择5mDEM、基于真实田坎方法构建的1m梯田DEM和基于激光点云数据构建的高精度1 m DEM数据分别对研究样区的地形...[目的]研究基于梯田DEM的地形湿度指数,为深化黄土高原地区土壤水分的研究提供依据。[方法]以黄土高原地区梯田为研究对象,选择5mDEM、基于真实田坎方法构建的1m梯田DEM和基于激光点云数据构建的高精度1 m DEM数据分别对研究样区的地形湿度指数进行表达并作对比分析。[结果]3种不同梯田DEM数据对地形湿度指数的表达有显著差异。(1)5m DEM数据仅能表现出地形湿度指数的宏观分布特征,不具备梯田地形特征信息;(2)基于真实田坎方法构建的1m梯田DEM能较准确细致地实现对梯田样区地形湿度指数的表达,梯田田面和田坎特征分布明显。但与高精度1 m DEM相比,在单个田面和田坎内部地形湿度指数定量表达有所偏差。[结论]基于真实田坎方法构建出的梯田DEM可以更加准确地表达出梯田区域的地形湿度指数分布特征,但与真实地形相比,在田面和田坎内部的表达上仍然有所偏差,其构建方法需要进一步改进。展开更多
基金This work was financially supported by project 133/2016/RPP-TO-1/b“Teaching of advanced techniques for geodata processing for follow-up study of geoinformatics”.
文摘As a GIS tool,visibility analysis is used in many areas to evaluate both visible and non-visible places.Visibility analysis builds on a digital surface model describing the terrain morphology,including the position and shapes of all objects that can sometimes act as visibility barriers.However,some barriers,for example vegetation,may be permeable to a certain degree.Despite extensive research and use of visibility analysis in different areas,standard GIS tools do not take permeability into account.This article presents a new method to calculate visibility through partly permeable obstacles.The method is based on a quasi-Monte Carlo simulation with 100 iterations of visibility calculation.Each iteration result represents 1%of vegetation permeability,which can thus range from 1%to 100%visibility behind vegetation obstacles.The main advantage of the method is greater accuracy of visibility results and easy implementation on any GIS software.The incorporation of the proposed method in GIS software would facilitate work in many fields,such as architecture,archaeology,radio communication,and the military.
文摘为探究精细化机载点云数据在大比例尺地形图测绘中的应用效益,提高基于机载点云数据绘制数字地形图的精度,选取了建模难度较大的带状地形作为测区,并获取了点云模型。使用Li DAR 360软件对点云数据进行精细化预处理,提高了点云模型的地面拟合度。结合点云模型与三维实景模型绘制1∶500的大比例尺地形图,并根据GPS-RTK获取的100个校核点对地形图精度进行了分析。研究结果表明:采用模型质量和测绘专项需求精细化处理方法可提高点云模型的地面拟合度,且绘制的地形图满足1∶500大比例尺地形图的绘制要求。
文摘[目的]研究基于梯田DEM的地形湿度指数,为深化黄土高原地区土壤水分的研究提供依据。[方法]以黄土高原地区梯田为研究对象,选择5mDEM、基于真实田坎方法构建的1m梯田DEM和基于激光点云数据构建的高精度1 m DEM数据分别对研究样区的地形湿度指数进行表达并作对比分析。[结果]3种不同梯田DEM数据对地形湿度指数的表达有显著差异。(1)5m DEM数据仅能表现出地形湿度指数的宏观分布特征,不具备梯田地形特征信息;(2)基于真实田坎方法构建的1m梯田DEM能较准确细致地实现对梯田样区地形湿度指数的表达,梯田田面和田坎特征分布明显。但与高精度1 m DEM相比,在单个田面和田坎内部地形湿度指数定量表达有所偏差。[结论]基于真实田坎方法构建出的梯田DEM可以更加准确地表达出梯田区域的地形湿度指数分布特征,但与真实地形相比,在田面和田坎内部的表达上仍然有所偏差,其构建方法需要进一步改进。
