共查询到19条相似文献,搜索用时 78 毫秒
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介绍了用于海量数字高程模型数据的管理、应用分析以及可视化的系统GeoDEMDB,采用部件对象模型技术,实现了数据管理、空间分析和大范围三维场景漫游的集成,并提供了灵活的选择性。 相似文献
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提出基于方差-尺度规律的新型插值方法评价体系,根据“在给定研究区域内,变量的统计方差随尺度增大而减小”的理论规律,提出三项预设的评价准则。以DEM插值应用为例,选取高精度曲面模型、样条插值、克里金插值、反距离权重插值4种方法进行对比评价。数值实验表明,方差-尺度递变趋势的评价准则值得存疑。两组DEM插值案例表明,地形的复杂特性、插值算子的光滑效应以及尺度的综合效应致使理论的渐变规律无法达到。引入采样方差值后,不同采样密度下仍可以将方差变化趋势及方差的整体大小作为精度评价准则,在对第二、第三条预设评价准则修缮后确立三项评价准则。综合所有案例可知,此评价体系原理简单、操作方便,为DEM插值方法评价提供了一套新的标准和框架,并且可针对不同采样密度条件提出完善的插值方法适用性建议。 相似文献
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在数字高程模型(digital elevation model,DEM)建模过程中,经典空间插值方法均没有考虑断裂线附近的局部地形特征影响,使得断裂线局部区域高程被平滑,从而导致地形特征失真。为了解决该问题,构造了一种顾及断裂地形特征的定权方法,并以径向基函数(radial basis function,RBF)为插值算子,提出了加权径向基函数方法。首先通过捕捉每个采样点的结构张量,自适应计算采样点与待求点的距离,然后利用该距离对每个采样点赋予合适的权重,最后利用加权插值实现DEM建模。以10组国际摄影测量和遥感学会公共数据和1组山体滑坡区域的机载激光雷达点云数据为例,利用所提方法构建样区DEM,并将计算结果与标准RBF及传统插值算法(如反距离加权法、克里金法、约束不规则三角网法)进行比较。精度分析表明,不论采样点数为多少,所提方法计算精度均优于其他插值方法;对DEM山体阴影图分析表明,相较于传统插值方法,所提方法能较好地保持断裂线局部地形特征。 相似文献
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自动构建复杂地质体数字高程模型的方法研究 总被引:22,自引:1,他引:22
本文提出了在建立空间图形点、线、面拓扑结构的基础上利用判断点合法性的正负区判别准则构建数字高程模型(DEM)的方法,为包括逆断层在内的复杂地质体的正确描述及图形的自动处理奠定了基础。 相似文献
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在生产或生活中应用数字高程模型内插时,最关键的问题就是怎样选取恰当的内插方法来满足高程数据建模的需求。不同的DEM内插方法随地貌地区和采样点方式的不同存在不同的误差。本文使用V isual Basic语言将数字高程模型内插方法编写成一套能够快捷方便的获取内插点高程的内插软件系统,可以使应用人员直接捕捉地面点高程,并获得地形的可视化信息,由此可以直观地观察到在同一地区相同采样点方式的条件下采用不同的内插方法引起的内插精度等质量方面的优劣区别,从而获取最优的内插方法,有效地满足DEM的生产、质量控制、精度评定和分析应用等各个环节。 相似文献
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针对机载LiDAR点云数据后处理中的现有粗差剔除方法存在需要大量人工干预或普适性差的缺点,该文在使用高程直方图剔除显著的高位、低位粗差的基础上,利用KD-树组织机载LiDAR点云数据,通过判断当前点与其k个最邻近点的平均距离远近来自适应地识别粗差点。实验结果表明:该算法具有参数较稳健、粗差剔除效果较好、效率较高的优势。 相似文献
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讨论对LIDAR点云的高程值进行再次改正的必要性和改正方法,提出构建Delaunay三角网对LIDAR点云的高程值进行再次改正的方法,实例改正结果表明,改正后的LIDAR点云的高程精度能够大幅度提高。 相似文献
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This paper presents a component object model (COM) based framework for managing, analyzing and visualizing massive multi-scale digital elevation models (DEMs). The framework consists of a data management component (DMC), which is based on RDBMS/ORDBMS, a data analysis component (DAC) and a data render component (DRC). DMC can manage massive multi-scale data expressed at various reference frames within a pyramid database and can support fast access to data at variable resolution. DAC integrates many use-ful applied analytic functions whose results can be overlaid with the 3D scene rendered by DRC, DRC provides view-dependent data paging with the support of the underlying DMC and organizes the potential visible data at different levels into rendering. 相似文献
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WANGYongjun GONGJianya 《地球空间信息科学学报》2003,6(3):32-36
This paper presents a component object model (COM) based framework for managing, analyzing and visualizing massive multi-scale digital elevation models (DEMs). The framework consists of a data manage-ment component (DMC), which is based on RDBMS/ORDBMS, a data a-nalysis component (DAC) and a data render component (DRC). DMC can manage massive multi-scale data ex-pressed at various reference frames within a pyramid database and can support fast access to data at variable resolution. DAC integrates many use-ful applied analytic functions whose re-sults can be overlaid with the 3D scene rendered by DRC. DRC provides view-dependent data paging with the sup-port of the underlying DMC and or-ganizes the potential visible data at dif-ferent levels into rendering. 相似文献
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In tropical forests, the penetration ability of airborne laser scanning (ALS) may be limited because of highly dense vegetation cover. However, in the typical planning of ALS surveys, the ability of laser pulses to penetrate forests is not considered. Nine round-trip flight lines covering the area of a tropical forest on the northeast side of the Tsengwen Reservoir in Taiwan were designed in this study. Five flight lines flew at altitudes of 1.525, 1.830, 2.135, 2.440, and 2.745 km, and the other four had pulse repetition frequencies (PRFs) of 100, 150, 200, and 250 kHz. The laser penetration index (LPI) is a quantitative index measuring the penetration ability of the ALS and consists of the ratio of the number of laser pulses reaching the forest floor to the total number of laser pulses. The LPI was used to represent the laser penetration rate and investigate the influence of flying altitude and PRF on the LPI. The results showed that as the flying altitude decreased by 1 km, the average LPI increased by 10%, and as the PRF decreased by 50 kHz, the average LPI increased by 2%. The effect of the LPI on digital elevation models (DEMs) was confirmed by visual images obtained by DEMs at five altitudes. The DEM obtained at an altitude of 2.745 km was coarsely textured, whereas that obtained at an altitude of 1.525 km was finely textured. The in-situ height data obtained from the electronic Global Navigation Satellite System (eGNSS) were compared with the data of the ALS-generated DEMs. The results indicated that when the LPI ≥60%, the height difference between the in situ data and DEM data was not prominent. However, when the LPI <60%, the ALS-derived DEM could be higher or lower than the in-situ height; the largest difference between the two was 1.7 m. The LPI of a forest should be considered for ALS survey planning, especially when consistent DEM precision for large tropical forest areas is paramount. 相似文献