共查询到19条相似文献，搜索用时 141 毫秒
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大型立交桥是城市交通的重要组成部分,也是城市地区中最为复杂的地物之一。立交桥三维可视化建模是数字化城市建设的重要课题,然而其复杂的几何与拓扑结构导致许多传统的统一建模方法无法正确表达其特征,一些商业软件中的表达方法又过于抽象,无法提供直观的感受以及交互式的处理。本文提出一种基于机载LiDAR数据的大型立交桥建模方法。主要特点包括：1）采用了分割后建模的策略,提出了自动的立交桥结构分割方法,能够将复杂的交汇、分叉结构分割成多个结构简单的区段,为后续建模工作打下了重要基础;2）在轮廓中确立约束边,采用全约束三角网建模方法,建立了立交桥三维可视化模型;3）利用区段建模信息结合先验知识检测并恢复被遮挡的结构。实验结果表明,本文先分割后建模的思想在复杂结构立交桥的建模问题上可以取得令人满意的结果,全约束三角网建模的方法很好的保留了模型的三维特征,更重要的是可用于恢复被遮挡的结构,从而使得模型具有完整的三维结构。整个模型在地理位置,几何尺寸以及拓扑关系上均与实际地物保持一致,具备三维浏览以及交互式操作的条件。对模型质量和算法效率的分析进一步说明了本文方法的可行性、有效性。 相似文献
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城市大型立交桥的三维可视化是数字化城市建设的重要课题,为解决常规三维建模过程中存在的制作周期长、工作量大以及多层立交桥存在遮挡导致数据缺失等诸多问题,结合车载激光扫描系统的特点及优势,本文提出采用车载激光扫描进行城市大型立交桥三维建模技术实现方法,得到了一套可行的数据采集工艺和三维建模技术实现方案。以北京西三环南路丽泽桥三维建模为例,进行了立交桥车载扫描外业点云数据采集、内业数据处理、三维边线提取、立交桥三维建模,从而证明车载激光扫描系统用于建立高精度城市立交桥三维模型的可行性。 相似文献
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基于机载LiDAR数据的大型立交桥自动提取与建模方法 总被引：1，自引：0，他引：1
提出一种基于机载LiDAR数据的大型立交桥建模方法。在提取立交桥数据点的基础上,采用先分割后建模策略,提出并实现立交桥结构自动分割方法,将复杂的交汇、分叉结构分割成多个结构简单的区段。在建模过程中,从轮廓中确立约束边,采用全约束三角网建模方法,建立立交桥三维可视化模型。最终利用区段建模信息结合先验知识检测并恢复被遮挡的结构,实现完整结构的真三维建模。试验结果表明,设计及流程在复杂结构立交桥的建模问题上可以取得令人满意的结果。整个模型在地理位置,几何尺寸以及拓扑关系上均与实际地物保持一致,具备三维浏览以及交互式操作的条件。对模型质量和算法效率的分析进一步说明其可行性与有效性。 相似文献
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大型立交桥的三维实景模型是数字城市建设的重要内容之一，可以为桥下空间梳理提供所需的实景三维参考数据。本文从实际生产应用的角度出发，针对三维模型生产周期长、点云采集工作量大且易存在数据“空洞”等问题，研究了基于多源三维激光点云数据进行大型互通式立交桥三维建模的方法，并得出了可行的数据采集和三维建模方案。以天宁寺桥为试验对象，利用车载、背包以及手持三维激光扫描系统采集高精度、高密度的三维点云数据，同时利用EPS实现半自动化立交桥结构线采集，参考点云数据基于3D Max平台实现对立交桥、河道及附属设施的三维建模，证明了利用多源点云数据进行大型互通式立交桥建模的可行性和有效性。 相似文献
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针对现有建筑物多细节层次（level of detail,LOD）表达主要面向外部,很少涉及内部空间的问题,提出一种含室内空间结构的建筑物三维LOD概念模型。该模型分为LOD0~LOD6 7个LOD,细节层次由建筑物的基底平面图、幢模型、无侧面楼层模型、楼层模型、户模型、房间模型到含门、窗等建筑语义的信息房间模型,空间细节逐次变细,丰富了建筑物室内空间LOD的表达理论。为构建这种LOD模型,提出基于胞腔复形链边界算子和上边界算子的LOD生成方法。该方法引入代数拓扑的胞腔、胞腔复形和复形链3个概念,利用胞腔和胞腔复形表达LOD,并在LOD6的基础上,利用边界算子和上边界算子生成其他粗空间粒度LOD模型,为三维城市模型建筑物LOD构建提供一种新方法。 相似文献
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针对以点云为基础进行建筑物三维建模时存在的点云数量庞大、构网复杂等问题,提出了一种基于倾斜影像线特征进行建筑物三维模型快速重构的方法。首先对三维线特征进行仿射平面剖分以及构建特征角点;然后以特征角点为引导基于拓扑顺序进行平面构建;接着采用各种规则构建与补充平面边界形成平面块,对模型进行精纠正后生成最后的建筑物三维模型。实验结果表明,该方法可基于线特征自动完成建筑物三维模型的重构,建模效率远高于基于点特征的三维建模,且精度符合要求,其为非精细化城市建筑模型的快速批量自动构建提供了高效且实用的解决方案。 相似文献
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建筑物的建模是数字城市中最重要的问题之一。通过分析城市建筑物的特点和分类，提出了利用CSG技术表达城市建筑物；通过分析建筑物组成对象层次，提出利用CSG基本对象的六个方位来建立建筑物内部的空间拓扑关系。 相似文献
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The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air, and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper, authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road, surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data structure for cloverleaf junction in 3DCM is proposed. 相似文献
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CHEN JunSUN MinZHCXJ Qiming Professor National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu Road Wuhan China 《地球空间信息科学学报》1999,2(1):9-15
The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data structur 相似文献
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基于几何元素的三维景观实体建模研究 总被引：1，自引：0，他引：1
在分析已有国内外研究成果的基础上 ,提出了基于几何元素的 3DCM空间数据模型。实验证明 ,该模型能较精确地表达 3DCM中各类景观实体及其空间关系。 相似文献
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3D city models are widely used in many disciplines and applications, such as urban planning, disaster management, and environmental simulation. Usually, the terrain and embedded objects like buildings are taken into consideration. A consistent model integrating these elements is vital for GIS analysis, especially if the geometry is accompanied by the topological relations between neighboring objects. Such a model allows for more efficient and errorless analysis. The memory consumption is another crucial aspect when the wide area of a city is considered – light models are highly desirable. Three methods of the terrain representation using the geometrical–topological data structure – the dual half-edge – are proposed in this article. The integration of buildings and other structures like bridges with the terrain is also presented. 相似文献
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LI DerenWANG YandongZHU QingGONG Jianya LI Deren Academician Professor National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu 《地球空间信息科学学报》1999,2(1):21-25
Data acquisition and modeling are the two important, difficult and costful aspects in a Cybercity project. 2D-GIS is mature and can manage a lot of spatial data. Thus 3D-GIS should make the best of data and technology of 2D-GIS. Construction of a useful synthetic environment requires integration of multiple types of information like DEM, texture images and 3D representation of objects such as buildings. In this paper, the method for 3D city landscape data model and visualization based on integrated databases is presented. Since the data volume of raster are very huge, special strategies(for example, pyramid gridded method) must be adopted in order to manage raster data efficiently. Three different methods of data acquisition, the proper data structure and a simple modeling method are presented as well. At last, a pilot project of Shanghai Cybercity is illustrated. 相似文献
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Data acquisition and modeling are the two important, difficult and costful aspects in a Cybercity project. 2D-GIS is mature and can manage a lot of spatial data. Thus 3D-GIS should make the best of data and technology of 2D-GIS. Construction of a useful synthetic environment requires integration of multiple types of information like DEM, texture images and 3D representation of objects such as buildings. In this paper, the method for 3D city landscape data model and visualization based on integrated databases is presented. Since, the data volume of raster are very huge, special strategies (for example, pyramid gridded method) must be adopted in order to manage raster data efficiently. Three different methods of data acquisition, the proper data structure and a simple modeling method are presented as well. At last, a pilot project of Shanghai Cybercity is illustrated. 相似文献
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由于缺乏有效并具有针对性的方法以及传统遥感影像的2维局限性,城市立交桥点的识别与轮廓提取存在较大困难。本文基于机载LiDAR点云数据提出一种城市立交桥的提取方法。首先,通过基于局部平面约束的剖面点分割方法,利用多方向扫描线建立改进的剖面邻域点云组织结构,从而提取出立交桥种子点。然后,利用Alpha-shape算法定位立交桥轮廓,并获取立交桥初始点。最后,利用区域增长的方法提取出完整结构,同时获取立交桥轮廓。实验结果表明,从提取结果上获取的立交桥长度、宽度以及形态等指标与人工量测结果相近,具有较高的准确度。 相似文献