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《The Cartographic journal》2013,50(3):293-299
AbstractAlthough people rarely think of relief models when speaking about cartographic products, these artefacts are probably the most impressive way of visualizing landscapes. Unlike traditional maps or globes, most relief models are unique, vulnerable hand-made objects. Digital archiving is an important step in their preservation. There are special tools for this task, but these equipments are rather expensive, and libraries or other institutes that usually own these models cannot spend too much. The authors examined various on-line tools to create digital 3D representation of relief models using a set of photographs as source. These tools create point cloud and textured triangle mesh based on matching patterns on the photos. A workflow was developed which uses these web services and produces the digital 3D version of relief models. This paper introduces the method, discusses the details of successful photographing, the possible post-processing of the results. A new web site, using the X3DOM technology to show the digitized models to the general public, is also introduced. 相似文献
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The automatic generation of 3D as-built models from LiDAR data is a topic where significant progress has been made in recent years. This paper describes a new method for the detection and automatic 3D modelling of frame connections and the formation of profiles comprising a metal frame from LiDAR data. The method has been developed using an approach to create 2.5D density images for subsequent processing using the Hough transform. The structure connections can be automatically identified after selecting areas in the point cloud. As a result, the coordinates of the connection centre, composition (profiles, size and shape of the haunch) and direction of their profiles are extracted. A standard file is generated with the data obtained from the geometric and semantic characterisation of the connections. The 3D model of connections and metal frames, which are suitable for processing software for structural engineering applications, are generated automatically based on this file. The algorithm presented in this paper has been tested under laboratory conditions and also with several industrial portal frames, achieving promising results. Finally, 3D models were generated, and structural calculations were performed. 相似文献
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AbstractWith the rapid development of 3D Digital City, the focus of research has shifted from 3D city modeling and geo-database construction to 3D geo-database service and maintenance. The frequent modifications on geometry, texture, attribute, and topology present a great challenge to the 3D geo-database updating. This article proposes an event-driven spatiotemporal database model (ESDM) that combines the historical and present 3D city models with the semantic classification and state expression, triggered by changing events predefined. In addition, a corresponding dynamic updating method based on adaptive matching algorithm is presented to perform the dynamic updating operation for the complex 3D city models automatically, according to the compound matching of semantics, attributes, and spatial locations. Finally, the validity and feasibility of the proposed ESDM and its updating method are demonstrated through a 3D geo-database with more than 1.5 million 3D city models. 相似文献
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给出了3维导航的基本概念;详细总结了国内外3维导航技术研究及产品开发的情况;概要分析了3维导航场景表示策略及建模方法、3维导航与2维导航配合使用、3维导航地理数据保障等相关核心技术问题;简要介绍了我们在3维导航方面所做的工作,并提出了几点建议。 相似文献
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大场景VRML在OpenGL中的实现--以北京市西城区为例 总被引：2，自引：1，他引：1
在建立数字北京时,为了利用现有的北京市西城区VRML格式的三维模型数据,分析了VRML的文件格式,并将该格式的数据转入到OpenGL编程易于实现的格式中。基于该数据量之大,将转出的数据变换到绝对坐标系中,从而实现了模型的动态调度和显示,并在OpenGL编程中实现。 相似文献
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ABSTRACTCity models have a wide variety of uses that require different kind of data representation or data models. Having a dynamic model that enables picking the right representations (meshes, volumetric data, point cloud, etc.) can prove useful to adapt an application to each user's needs. In this paper, we present an original method to create personalised visualisations of 3D city models on the fly. By organising the server data in a hierarchy of tiles, we are able to generate personalised models based on the user's preferences. These preferences take the shape of a set of rules that apply to each tile or city object and allow the user to choose which representation of the object to use depending on its position or semantic information (classification, height, etc.). Our method is designed around existing standards, guaranteeing the interoperability of the produced models. 相似文献
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《International Journal of Digital Earth》2013,6(2):91-105
The effect of Digital Earth on our life is vital. Developing and updating Geospatial data in Digital Earth is also essential. This paper presents the application of a new approach of image registration in Digital Earth. The approach was developed based on registering a mono photograph on a master 3D model. The result is a 3D vector model, which can be broadly applied in visualisation, mapping, geographic information system (GIS), planning, change detection, as well as Digital Earth. The approach does not require parameters of correction for transformation. The accuracy of the output depends on the accuracy of the master data. This approach is very versatile and able to register any image on the digital elevation model, digital surface model and topographic 3D model. 相似文献
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三维计算机模拟模型是遥感辐射传输机理研究的重要内容,在复杂地表正向模拟和遥感反演中扮演着重要角色。经过最近20年的发展,三维计算机建模研究取得了显著进展,在地表辐射传输过程分析、模型和算法的验证及遥感反演等方面应用广泛。为了更加充分理解三维计算机模拟模型的发展和模型间的差异,及探讨如何将其更好的应用于生活、生产,本文对三维计算机模拟模型在光学遥感的研究进行了综述。本文从模型的原理、应用和发展趋势3个方面展开了论述。首先,简要介绍了光线追踪方法和辐射度方法的原理及现有的模型;然后,对三维计算机模拟模型在遥感的主要应用进行了总结;最后,对模型未来的发展趋势展开了讨论,从运行效率、模拟精度和功能集成等方面存在的问题和需求出发,分析了三维计算机模拟模型发展和遥感应用的趋势。随着复杂地表遥感建模研究的深入,计算机技术的发展和多源遥感数据特别是高时空分辨率数据的应用,三维计算机模拟模型将在遥感理论研究和应用发挥更加重要的作用。 相似文献
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一种3维建筑物模型的数据描述及采集方案 总被引：1，自引：0，他引：1
随着“数字地球”、“数字城市”概念的不断深化,作为“数字城市”最基础、最关键的技术,3维城市模型数据的制作已经成为数字化测绘的新技术亮点。本文介绍了一种3维城市建筑物模型的数据存储结构,详细阐述了不同类型3维建筑物的采集方法,由此总结出3维建筑物模型数据的生产、存储、表述的完整方案。 相似文献
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城市是一种人地关系系统,数字城市是物质城市在数字网络空间的再现和反映。城市GIS是数字城市的核心,通过对3维GIS的介绍,主要探讨了3维GIS在城市3维景观建模中的作用和方法,并且对3维GIS在城市3维景观中的应用目标、功能、方法及其展望做了初步的探究。 相似文献
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3维GIS面向对象数据模型的研究与应用 总被引：5，自引：2，他引：5
3维数据模型是3维GIS研究中亟待解决的一个核心问题。在充分分析现有3维数据模型的基础上，从实际应用出发，针对传统模型的不足，提出1种3维GIS面向对象数据模型，以解决空间不规则实体本身，以及实体间复杂关系的描述、表达和组织等关键问题，并给出此模型应用实例，证明此模型的可行性和实用性。 相似文献
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《The Cartographic journal》2013,50(1):20-23
AbstractThe rapid development of physically-based hydrological information and modelling systems has necessitated enhanced data entry and display systems. A 'mapping tool' is developed for the manipulation and display of spatial information, which is a cost-efficient, self-contained utility system that is suitable for use on micro-computers. It has the ability to be integrated as part of any modelling or information system. Diverse applications using the 'mapping tool' are briefly described including resource management systems for planners, mass balance studies in urban catchments and data entry systems for physically based models. 相似文献
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为建立一种简易的FLAC3D建模方法,降低FLAC3D前处理时的建模难度,本文基于Python编程语言开发了建模文件生成程序。该程序以岩体各层位的高程信息为基础,采用Kriging插值生成离散网格点数据;并采用离散网格点自动生成建模所需要的网格数据文件;将该文件导入FLAC3D软件中,即可生成与真实钻孔数据和地层信息吻合的三维模型。程序提供了3种FLAC3D内置单元模型可供选择。该方法采用Kriging插值算法,可生成精确的三维地层模型数据。与FLAC3D软件自身的脚本建模语言相比,该方法简单快速。本文使用3类应用数据进行建模,验证提出的插值建模方法可以针对复杂的地形和地质信息生成精确的三维模型。研究成果为采用FLAC3D进行复杂地质区域数值模拟计算提供了一种简单、高效、准确的建模工具。 相似文献
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Pawel Boguslawski Christopher M. Gold 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(2):188-197
While CityGML permits us to represent 3D city models, its use for applications where spatial analysis and/or real-time modifications are required is limited since at this moment the possibility to store topological relationships between the elements is rather limited and often not exploited. We present in this paper a new topological data structure, the dual half-edge (DHE), which permits us to represent the topology of 3D buildings (including their interiors) and of the surrounding terrain. It is based on the idea of simultaneously storing a graph in 3D space and its dual graph, and to link the two. We propose Euler-type operators for incrementally constructing 3D models (for adding individual edges, faces and volumes to the model while updating the dual structure simultaneously), and we also propose navigation operators to move from a given point to all the connected planes or polyhedra for example. The DHE also permits us to store attributes to any element. We have implemented the DHE and have tested it with different CityGML models. Our technique allows us to handle important query types, for example finding the nearest exterior exit to a given room, as in disaster management planning. As the structure is locally modifiable the model may be adapted whenever a particular pathway is no longer available. The proposed DHE structure adds significant analytic value to the increasingly popular CityGML model. 相似文献
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"数字校园"建设是科技发展的必然趋势,为加快这一进程,本次研究将地面三维激光扫描技术应用到大学校园。本文以Z+F IM AGER 5010c地面三维激光扫描仪采集到的吉林建筑大学基础实验楼数据为基础,运用3ds max、Auto CAD、Point Cloud等建模软件建立三维模型。同时将依据点云数据建立的实体模型与实际测量数据进行对比和精度分析,验证了地面三维激光扫描仪在建筑物三维模型建立中的精度和可靠性。 相似文献