共查询到19条相似文献，搜索用时 156 毫秒
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地表空间水文过程三维可视化试验——以浙江黄土岭流域为例 总被引：1，自引：0，他引：1
地表空间水文过程涉及三维地理空间和一维时间,对其进行三维动态交互显示便于认知主体对水文过程形成正确的认识。本文以浙江黄土岭流域为试验区,结合地理信息系统和计算机图形学的方法和技术探究了流域空间水文过程的动态交互显示方法。利用OpenGL的三维建模和图像渲染功能表现三维的水文过程,其中双缓冲技术保障了水文过程时间变化的展示。探讨了表面建模,地形着色处理,光照法线计算,水体透明处理,时相水文数据处理及交互参数输入等方法,并建立了地表空间水文过程的显示系统。通过系统的运行表明,该系统能逼真地显示不同高程连续水体的三维动态变化。 相似文献
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基于钻孔的三维地质模型快速构建及更新 总被引：1，自引：0，他引：1
明镜 《地理与地理信息科学》2012,28(5):55-59,113
为利用钻孔数据快速构建三维地质模型并进一步提高模型合理性和数据质量,提出了基于钻孔的三维地质模型快速构建及更新方法.利用基于层位标定的钻孔数据快速解译方法完成原始钻孔中地层分界点的编号之后,实现了三维模型的自动构建;通过在约束条件下调整层面虚拟控制点,完成了模型的交互式调整,并能根据调整结果自动更新三维模型.该方法在建模实际案例中的成功应用,证明其能够很好地处理工程实践中的复杂问题,提高了建模效率及模型质量. 相似文献
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地理遥感信息模型是在地形模型、物理模型、数学模型的基础上提出的一种新型模型。面向对象技术是一种新型的系统建模技术。该文论述面向对象技术应用于地理遥感信息模型建模的可行性 ,以面向对象技术基本理论为指导 ,采用面向对象分析方法 ,将地理事物分类、抽象成具有一定地理意义的独立因子团 (即面向对象模型中的对象和类 )。提出了面向对象的地理遥感信息模型的建模方法、数据结构以及建模优势 相似文献
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王琪 《地理与地理信息科学》2007,23(2):39-42
网络环境下进行二维电子地图与三维虚拟场景集成,关键问题之一是数据快速、有效地传输与表达。为了解决网络电子地图与三维虚拟场景集成过程中数据快速传输问题,该文讨论了空间数据多级存储、网络数据流压缩、矢栅数据有机结合、纹理模型及原型模型库等网络传输瓶颈解决方案和模型数据简化方法,为后续网络电子地图和三维虚拟场景集成系统的开发奠定基础。 相似文献
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面向对象的地理遥感信息模型 总被引：2，自引：0，他引：2
地理遥感信息模型是在地形模型，物理模型。数学模型上提出的一种新型模型。面向对象技术是一种新型的系统建模技术，该文论述面向对象技术应用于地理遥感信息模型建模的可行性，以面向对象技术基本理论为指导，采用面向对象分析方法，将地理事物分类，抽象成具有一定地理意义的独立因子团（即面向对象模型中的对象和类）。提出了面向对象的地理遥感信息模型的建模方法，数据结构以及建模优势。 相似文献
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《地理与地理信息科学》2017,(4)
基于GIS的数字地形分析的理论、方法与应用是地理信息科学研究的热点问题。目前公路微地形模型缺失对汇水要素的完整表达,且汇水分析绝大部分用于自然地表模型,较难开展汇水要素约束下的公路微地形的水文分析。该文利用公路排水设计在内的公路设计数据,提取公路微地形的水文信息与高程信息,基于公路微地形三维中心线构建、横断面坐标系转换、汇水要素添加等方法流程,构建汇水要素约束下的公路微地形三维模型,在此基础上,完成公路微地形三维模型可视化表达并实现公路微地形水文分析。研究结果表明,面向水文分析的公路微地形三维建模方法,可满足公路微地形三维模型可视化与水文分析应用的双重需求,为我国公路的设计、建设、运行及维护等方面做出贡献。 相似文献
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三维遥感信息处理系统的设计和应用 总被引：3，自引：0，他引：3
利用机载三维遥感技术能够同步获取三维位置和光谱数据的一体化信息。三维遥感信息处理系统利用获取的三维遥感数据生成遥感地学编码图像和DEM（数字表面模型）。该文阐述了此信息处理系统的数据处理流程和软件构成，同时对该系统的各处理模块进行了描述，通过对中关村地区300多km^2的三维遥感信息数据的处理，检验了三维遥感信息处理系统的可行性。 相似文献
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将地貌综合的三维Douglas-Peucker方法引入地形LOD中,通过构建Quad_TIN模型,结合离散点的全局重要性分级、地形块的四叉树模型构建、高效的可见性判断及增量更新等策略,提出一种大规模地形实时动态显示的新算法。实验结果表明,在保证地形的自适应快速、逼真显示的前提下,可大大扩展三维Douglas-Peucker和Quad_TIN的适用范围及运算效率,为海量三维场景的逼真快速重构提供了现实可能性。 相似文献
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Mengyun Zhou Jianya Gong 《International journal of geographical information science》2016,30(11):2208-2229
Polygonal vector data are important for representing countries, lakes, residential settlements, and other polygonal features. The proper representation of polygonal vector data is the basis of efficient rendering and picking and quick access and display of the analysis results based on polygons (e.g., 3D overlaying and surface area measurement in mountainous areas) in a virtual globe. However, polygonal vector data are displayed using texture-based or boundary-based approaches in most existing virtual globes. The texture-based approach cannot easily support interactive operations (e.g., picking) and spatial analysis (e.g., adjacency analysis and spatial measurement). The boundary-based approach treats the holes as independent features; however, it is difficult to recognize which boundaries constitute a polygon. Further research is needed on how to better organize the polygons to support efficient rendering, picking, and analysis in a virtual globe. In this article, we propose two methods to drape interior filled 2D polygons onto a multi-resolution 3D terrain. Both proposed methods combine polygon clipping and polygon triangulation. The difference between the two methods is in the way holes are eliminated. Method 1 recursively subdivides a terrain triangle until the child-triangles contain no holes; every resulting clipped polygon, which is then triangulated, contains no holes. Method 2 directly clips a polygon against a terrain triangle and creates bridge edges to transform the resulting polygons with holes to degenerate polygons that are further triangulated. The experimental results demonstrate that both proposed methods can efficiently process polygons with holes resulting in appropriate numbers of triangles. The processed interior-filled polygons remain close to the terrain surface in a virtual globe. Both proposed methods support real-time rendering of polygonal vector data in a virtual globe. 相似文献
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B. Yang W. Shi Q. Li 《International journal of geographical information science》2013,27(10):1019-1038
Multi‐resolution terrain models are an efficient approach to improve the speed of three‐dimensional (3D) visualizations, especially for terrain visualization in Geographical Information Systems (GIS). As a further development to existing algorithms and models, a new model is proposed for the construction of multi‐resolution terrain models in a 3D GIS. The new model represents multi‐resolution terrains using two major methods for terrain representation: Triangulated Irregular Network (TIN) and regular grid (Grid). In this paper, first, the concepts and formal definitions of the new model are presented. Second, the methodology for constructing multi‐resolution terrain models based on the new model is proposed. Third, the error of multi‐resolution terrain models is analysed, and a set of rules is proposed to retain the important features (e.g. boundaries of man‐made objects) within the multi‐resolution terrain models. Finally, several experiments are undertaken to test the performance of the new model. The experimental results demonstrate that the new model can be applied to construct multi‐resolution terrain models with good performance in terms of time cost and maintenance of the important features. Furthermore, a comparison with previous algorithms/models shows that the speed of rendering for 3D walking/flying through has been greatly improved by applying the new model. 相似文献
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基于GIS的采煤塌陷区土地复垦项目规划设计研究 总被引：4，自引：0，他引：4
土地开发整理是现阶段中国实现耕地总量动态平衡的重要途径,采煤塌陷区土地复垦是其中重要的组成部分。受塌陷沉降的影响,采煤塌陷区具有地形破碎、微地貌起伏交错和土壤养分流失严重等特点,其在土地复垦项目的规划设计中面临的问题较一般区域复杂。在分析采煤塌陷区土地复垦规划设计流程与方法的基础上,借助GIS技术,将地形图中等高线进行栅格化处理,并根据得到的数据生成三维地形模型,对项目区地形进行模拟,并分别从复垦适宜性评价、项目规划择优以及项目工程设计三方面进行了实证研究。 相似文献
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Çetin Koca 《International journal of geographical information science》2014,28(9):1821-1847
Terrain rendering is a crucial part of many real-time applications. The easiest way to process and visualize terrain data in real time is to constrain the terrain model in several ways. This decreases the amount of data to be processed and the amount of processing power needed, but at the cost of expressivity and the ability to create complex terrains. The most popular terrain representation is a regular 2D grid, where the vertices are displaced in a third dimension by a displacement map, called a heightmap. This is the simplest way to represent terrain, and although it allows fast processing, it cannot model terrains with volumetric features. Volumetric approaches sample the 3D space by subdividing it into a 3D grid and represent the terrain as occupied voxels. They can represent volumetric features but they require computationally intensive algorithms for rendering, and their memory requirements are high. We propose a novel representation that combines the voxel and heightmap approaches, and is expressive enough to allow creating terrains with caves, overhangs, cliffs, and arches, and efficient enough to allow terrain editing, deformations, and rendering in real time. 相似文献
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月面形貌仿真可以为嫦娥三号着陆前地形建立及视觉导航仿真测试提供逼真的三维月面环境。利用分形随机算法并结合月面撞击坑与石块的数学分布模型,在实现月面数字地形的基础上利用纹理映射和纹理融合的方法为月面地形添加纹理,完成了月面逼真三维环境的构建。结合导航相机的外方位元素和光照条件,实现了对该仿真月面环境的模拟环拍,支撑了嫦娥三号发射前月球车导航相机数据获取、地形建立、通行代价图计算、月球车路径规划等遥操作任务过程仿真测试。测试结果表明,仿真月面三维地形具有良好的视觉效果,满足了巡视器导航相机测试验证对精细月面地形和纹理的需求,为导航相机测试验证提供了有效的月面形貌仿真数据。 相似文献
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Brooke E. Marston Bernhard Jenny 《International journal of geographical information science》2013,27(7):1144-1165
Relief shading is the most common type of cartographic relief representation for print and digital maps. Manual relief shading results in informative and visually pleasing representations of terrain, but it is time consuming and expensive to produce. Current analytical relief shading can be created quickly, but the resulting maps are not as aesthetically appealing and do not show landscape features in an explicit manner. This article introduces an automated digital method that produces shaded relief with locally adjusted illumination directions to simulate the techniques and cartographic principles of manual relief shading. Ridgelines and valley lines are derived from a digital terrain model, vectorized, and used in a diffusion curve algorithm. A graph analysis generalizes the lines before using them for diffusion curve shading. The direction of illumination is adjusted based on the spatial orientation of ridgelines and valley lines. The diffusion curve shading is combined with standard analytical relief shading to create a final diffusion relief shading image. Similar to manual relief shading, major landforms and the structure of the terrain are more clearly shown in the diffusion relief shading. The presented method best highlights major landforms in terrain characterized by sharp, clearly defined ridges and valleys. 相似文献
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A dynamic model for rainfall-induced landslides on natural slopes 总被引：18，自引：0，他引：18
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为实现大规模地形的多分辨率显示与实时绘制,基于LOD技术给出了多尺度TIN的管理和表达算法。探讨该算法相关的数据组织、LOD层次表达、实时刷新等关键问题。该算法使用分级策略,在不影响视觉效果前提下对TIN进行分级表达;使用分区策略,在可视化过程中对TIN进行局部更新。采取不同分辨率TIN模型间逐步过渡策略,基本上消除了视图变换时的跳跃感。实验结果表明,这种紧凑有效的TIN表示方法实现简单,内存开销较少,CPU耗费小,大大缩短了视图刷新切换时间,能够在普通机器上实现大规模地形的实时漫游。 相似文献
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基于山地灾害动态过程仿真需要的考虑,并针对该动态过程仿真时渲染数据量过大所造成的实时性较差的问题,提出了利用改进的三角形二叉树LOD算法实现地形三维建模与可视化的方法。算法对山地地形数据进行了分层和分块的预处理,用三角形二叉树表示地形网格,并结合视点和局部地形的粗糙程度,动态的载入所需的地形块和释放无用的地形块,使得内存中的地形数据维持在一定范围内。实验结果表明;在对地形渲染不失真的前提下,本方法能够有效地提高地形绘制的效率,可应用到大规模山地地形的三维建模与可视化中去,为整个山地灾害的动态过程仿真奠定了良好的基础。 相似文献