基于骨架线的Douglas-Peucker算法改进   总被引：1，自引：0，他引：1  

陈惠荣  郑义东  关海波  徐卫明 《海洋测绘》2011,31(5):18-20

针对Douglas-Pecuker算法中以垂直距离为化简指标的不足,提出了以骨架线为化简指标的改进算法.在对曲线凸凹顶点识别基础上,通过三角网的构建实现了凸点到基线的骨架线的提取,结合Douglas-Peucker算法的一般步骤,进行了曲线化简实验和方法的比较,验证了改进算法在保持线要素形态特征上的合理性.  相似文献   

曲线化简的弧比弦算法改进及其评价     

刘慧敏  樊子德  徐震  邓敏 《地理与地理信息科学》2011,27(1):45-48

地图综合是当前国际GIS和制图学领域的一个难题。化简是地图综合的一个基本操作算子,线要素是地图综合操作的主要对象,该文主要研究地图线要素的化简问题。首先,从算法的适用范围、阈值设置等方面分析了现有算法的优点,重点阐述了一种常用的弧比弦算法,并指出了其在化简过程中存在的不足。然后,基于地图曲线的空间认知特征,提出了一种改进弧比弦算法。该算法能够更好地保持曲线的特征点和曲线的几何形态,避免阈值的设置问题。在算法评价上,采用3种定量评价指标,即:偏移平均值、偏移量中值和面积变形值,对改进的弧比弦算法与现有经典算法进行了比较分析。最后,通过算例分析验证了该算法的可行性、有效性和健壮性。  相似文献   

建筑物三维表面模型简化算法探讨   总被引：3，自引：1，他引：2  

王庆国  朱庆  艾廷华 《测绘科学》2007,32(2):84-86,132

模型简化是近年来计算机图形学中的一个研究热点,并已在虚拟现实、可视化、实时渲染、计算机视觉和渐进传输等众多方向得到广泛应用。本文针对3D建筑物表面模型的自动简化处理,首先对现有模型简化算法及各自的优缺点进行了归纳总结,分析了现有3D建筑物模型简化算法存在的问题,并探讨了3D建筑物表面模型的简化思路。  相似文献   

基于约束条件的线要素化简算法质量评估     

朱鲲鹏  武芳  陈波  薛本新 《测绘科学》2007,32(3):28-30

随着制图综合质量评价越来越受重视,对地图要素中所占比例最大的线要素的化简算法进行质量评估变得十分必要。结合线化简算法自身的特点,从几何和语义两方面总结了线要素在化简过程容易出现的问题,在分析线要素化简应满足的约束条件的基础上,提出对算法实施评估的评价指标,并选择水平中误差等三种评价指标对三种线化简算法具体实施质量评估。试验结果证明了本文提出的评估方法的科学性。  相似文献   

建筑物多边形化简及优化的自动方案研究     

袁策 《测绘科学》2007,32(6):84-85,32

针对居民地地图形状化简的一个方面——建筑物多边形的化简,通过对综合规则的研究和居民地几何特征的剖析,提出一种与比例尺相关的切割实现建筑物多边形化简的方法,在Visual Basic6.0环境下实现了该算法,试验结果表明此方法在保持街区的形态特征上效果较好。  相似文献   

基于特征约束的点云简化算法研究     

谢波  郑德华 《测绘与空间地理信息》2013,(12):163-165

针对传统的点云简化算法导致特征区域容易丢失的问题,提出了一种新的基于特征约束的点云简化的算法。首先对散乱点云用KD—TREE建立起空间拓扑关系,在此基础上建立起单个点的K-邻域。然后对K-邻域内建立起最小二乘平面,设定合理的阈值来度量数据点的重要性。依据特征点的分布估算每个点的简化距离阈值,以此为基础对每个点进行自适应简化。实验证明该算法能满足在点云数据简化过程中检测并保留特征点的要求。  相似文献   

一种基于CityGML的三维模型单体化方法     

倪晓东  梁君达  吴龙祥  刘沐洋 《测绘通报》2022,(12):29-34

实景三维中国建设应满足自然资源管理与社会经济发展需求,因此需要对基础地理信息产品进行实体化改造,三维模型单体化正是实体化改造的关键环节。本文提出了一种基于CityGML的三维模型单体化方法,首先根据地物实体轮廓的二维矢量面提供的顶点坐标及高程信息,构造墙面、屋顶等多边形平面组成地物的简单三维表达,然后配合渲染到纹理技术（RTT）进行纹理贴图,基于CityGML为每个二维矢量面对应的地物重构出有语义、有LOD层级的三维模型。该方法能够高效地实现三维模型单体化,且成果模型容量小,可满足各种实景三维应用需求。  相似文献   

保持移动速度特征的轨迹线化简方法     

杨敏  陈媛媛  金澄  程前 《测绘学报》2017,46(12):2016-2023

轨迹线数据实施化简处理对于缓解数据存储、传输压力以及后期的分析可视化效率具有重要意义。常规方法(如Douglas-Peucker算法)主要考虑线目标的几何形态结构,直接应用到轨迹线化简中容易丢失移动物体的运动状态特征。本研究从保持轨迹线隐含速度特征出发,提出了一种基于移动速度相似性原则的轨迹线层次化剖分与分区化简处理方法。首先,以相邻轨迹点构成的直线段为基本单元,在拓扑连接关系约束下基于速度指标对轨迹直线段进行层次化聚类,并将聚类结果组织为层次树结构;然后,以建立的层次树结构为约束条件对原始轨迹线实施分区处理,使得同一区域内轨迹线片段的中间点距首尾基准线的最大时间同步偏移距离小于设定的阈值;最后,依次连接各分区轨迹线片段首尾点导出化简结果。采用真实的车辆轨迹线作为试验数据,通过与其他多种方法进行对比分析验证了本文提出方法的有效性。  相似文献   

Visual Abstraction and Stylisation of Maps     

《The Cartographic journal》2013,50(1):8-18

Abstract

We explore visual map abstraction for the generation of stylized renderings of 2D map data. We employ techniques that are centred around the concept of shape simplification and graph layout and that allow iterative abstraction of 2D maps. We use data from publicly available sources and show how we can iteratively generate aesthetic renditions of these maps. These renditions do not have the goal to allow for navigation tasks, but instead show the map data in a distorted manner. The techniques used to create these images apply simplification, abstraction/generalisation, and displacement operations to the map elements in varying orders and add stylistic shading to produce aesthetic renditions for print or electronic displays. The degree of abstraction/generalisation can be individually chosen and determines the characteristics of the distorted map: whether components retain their shape, degenerate, or are processed in a manner that the abstraction becomes the focus of the image rather than the underlying map data. The renditions can be further personalized by choosing shading and colours for this shading. Together, the presented techniques allow for playful and creative exploration of aesthetic renditions of 2D map data.  相似文献   

Multicriteria generalization (MCG): a decision-making framework for formalizing multiscale environmental data reduction     

Gaurav Sinha  Warit Silavisesrith 《International journal of geographical information science》2013,27(5):899-922

Environmental simulation models need automated geographic data reduction methods to optimize the use of high-resolution data in complex environmental models. Advanced map generalization methods have been developed for multiscale geographic data representation. In the case of map generalization, positional, geometric and topological constraints are focused on to improve map legibility and communication of geographic semantics. In the context of environmental modelling, in addition to the spatial criteria, domain criteria and constraints also need to be considered. Currently, due to the absence of domain-specific generalization methods, modellers resort to ad hoc methods of manual digitization or use cartographic methods available in off-the-shelf software. Such manual methods are not feasible solutions when large data sets are to be processed, thus limiting modellers to the single-scale representations. Automated map generalization methods can rarely be used with confidence because simplified data sets may violate domain semantics and may also result in suboptimal model performance. For best modelling results, it is necessary to prioritize domain criteria and constraints during data generalization. Modellers should also be able to automate the generalization techniques and explore the trade-off between model efficiency and model simulation quality for alternative versions of input geographic data at different geographic scales. Based on our long-term research with experts in the analytic element method of groundwater modelling, we developed the multicriteria generalization (MCG) framework as a constraint-based approach to automated geographic data reduction. The MCG framework is based on the spatial multicriteria decision-making paradigm since multiscale data modelling is too complex to be fully automated and should be driven by modellers at each stage. Apart from a detailed discussion of the theoretical aspects of the MCG framework, we discuss two groundwater data modelling experiments that demonstrate how MCG is not just a framework for automated data reduction, but an approach for systematically exploring model performance at multiple geographic scales. Experimental results clearly indicate the benefits of MCG-based data reduction and encourage us to continue expanding the scope of and implement MCG for multiple application domains.  相似文献