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1.
面向对象的水利地理空间元数据库的研究与实现   总被引:2,自引:0,他引:2  
王永杰  苗丽  周新忠 《测绘科学》2007,32(5):127-129,149
论述了地理空间元数据的特点和组织结构,分析了已有元数据组织和管理模式的不足。在阐述面向对象核心思想的基础上,剖析了地理空间元数据的"对象"特质。然后以面向对象的思想对地理空间元数据重新加以认识和描述,提出了基于面向对象方法的地理空间元数据组织和管理模式,并设计实现了面向对象的水利地理空间元数据库,克服了已有模式的不足。  相似文献   

2.
大型立交桥三维建模方法研究   总被引:2,自引:0,他引:2  
胡碧松  龚建华 《测绘科学》2008,33(1):100-102,87
立交桥是一个由桥梁、空间交叉和毗邻建筑物等组成的复杂空间结构,在整个城市道路网中占有很重要的地位。由于立交桥其自身的空间结构的复杂性,三维建模有异于一般建筑物和地形,尤其是对于大型的立交桥,其空间跨桥错综复杂、拓扑关系繁多,建模工作更为困难。在已有的数字城市模型中,大型立交桥的三维建模一直是个亟待解决的难题。该文从大型立交桥的三维数据模型与拓扑结构的组织管理入手,提出其三维建模方法的一般流程,以西直门立交桥为实例取得良好的建模效果,最后提出优化大型立交桥三维模型的一些关键技术。  相似文献   

3.
张猛  曾永年  朱永森 《遥感学报》2017,21(3):479-492
以洞庭湖流域为研究区,对大范围湿地信息遥感提取方法进行了研究。先基于时间序列MODIS EVI及物候特征参数,通过J-M(Jeffries-Matusita distance)距离分析,构建了MODIS(250 m)最佳时序组合分类数据;其次,通过Johnson指数确定了最佳分割尺度,采用面向对象的遥感分类方法(Random tree分类器)提取了洞庭湖流域的湿地信息,并验证该方法的适用性。研究结果表明,基于时序数据与面向对象的Random tree分类的总体精度和Kappa系数分别为78.84%和0.71,较之基于像元的相同算法的总体分类精度和Kappa系数分别提高了5.79%和0.04。同时,基于面向对象方法的湿地整体的用户精度与生产者精度较基于像元方法分别提高了4.56%和6.21%,可有效提高大区域湿地信息提取的精度。  相似文献   

4.
殷亚秋  冷玥  赵玉灵  安娜  鞠星 《测绘通报》2019,(5):109-112,142
遥感信息获取过程中云是重要的干扰因素,随着国产高空间分辨率卫星数据的应用,实现数据的准确云检测对有效获取地面信息具有重要意义。本文以高分一号、高分二号多光谱影像为数据源,利用图像分割获取了同质对象,基于对象光谱、纹理和几何8种属性特征建立了规则集,以规则集为输入,利用阈值法和GURLS分类器结合进行了云检测。针对不同时相和场景的高分数据,将该方法与基于像素的最大似然法和SVM法进行了对比,结果表明该方法云提取精度均在95%以上,Kappa系数在0.9以上。  相似文献   

5.
利用GML模式映射屏蔽地理空间数据源的异构性   总被引:1,自引:0,他引:1  
本文分析了地理空间数据源的异构性以及GML模式的异构性;提出以GML模式对地理空间要素进行建模,构建适合空间信息共享的GML基本地物规范模式;通过应用模式的结构去屏蔽不同数据源结构的异构性,通过对应物属性去屏蔽编码语义的异构性,使空间信息的共享与互操作有统一的语义基础。  相似文献   

6.
1 lntroductionA Mraphical object normal1y poSSeSSes threecomPOnents: spatiaI, temporal and attribute asPeCts.The first comPOnent describes the spatial extent ofan object, such as the boundary of a Iand parcel.The second describes timesrelated information, fOrinstance, the beginning and end time of a land Par-cel. The third describes the attribute characteristicsof obects, fOr example, the type of land cover.These three comPOnents constitute a complete im-age of an object.In most of the…  相似文献   

7.
This paper presents a conceptual data model, the STA-model, for handling spatial, temporal and attribute aspects of objects in GIS. The model is developed on the basis of object-oriented modeling approach. This model includes two major parts: (a) modeling the signal objects by STA-object elements, and (b) modeling relationships between STA-objects. As an example, the STA-model is applied for modeling land cover change data with spatial, temporal and attribute components.  相似文献   

8.
基于空间分析的徐州市居民点分布模式研究   总被引:7,自引:1,他引:7  
闫庆武  卞正富  王桢 《测绘科学》2009,34(5):160-163
居民点空间分布的研究是聚落地理学的主要内容之一,运用空间分析的方法研究居民点的分布能更准确地刻画出其空间分布的本质规律。本文根据2004年TM遥感图像和城市地图得到徐州市城乡居民点空间分布的信息,继而运用样方分析(QA)法、最近邻距离指数(NNI)、K(d)函数、热点探测技术(NNH)研究了徐州市居民点空间分布格局与模式。结果显示:徐州市居民点的空间分布具有明显的空间依赖性,总体上呈现出集聚分布的特点;随着研究尺度的变大,居民点空间分布的集聚性指数也增大;居民点空间分布的热点区域在微观尺度上具有空间随机性、在中观尺度上具有轴带延伸性、宏观尺度上具有面状集中性的特点。  相似文献   

9.
A consistent theme in recent work on developing exploratory spatial data analysis (ESDA) has been the importance attached to visualization techniques, particularly following the pioneering development of packages such as SPIDER and REGARD (Haslett et al. 1990).  The focus on visual techniques is often justified in two ways: (a) the power of modern graphical interfaces means that graphics is no longer a way of simply presenting results in the form of maps or graphs, but a tool for the extraction of information from data; (b) graphical, exploratory methods are felt to be more intuitive for non-specialists to use than methods of numerical spatial statistics enabling wider participation in the process of getting data insights. However, little work has been done to decide which visualization tools might be needed to support ESDA, or how they can be most effectively implemented.  This paper briefly reviews a theoretical framework that has been suggested for addressing these issues, which comprises two elements: firstly a data model, based on the distinction between rough and smooth properties of spatial data, that defines what an analyst is looking for in data (Haining et al. 1998) and secondly a theoretical model for assessing the quality of visualisation tools (Cleveland 1994). The emphasis of this paper is the use of the theoretical framework to structure an assessment of SAGE, a software system that has been written for the spatial statistical analysis (including both exploratory and confirmatory data analysis) of area based data linked to a GIS. The aim of the assessment is to identify the desirable features of the system (that might be employed in other systems) whilst also highlighting what the additional requirements are thereby contributing to the development of systems for ESDA that contain good quality scientific visualization tools for exploratory spatial data analysis. Received: 30 September 1998/Accepted: 17 September 1999  相似文献   

10.
本论文面向"数字城市"的多源数据整合和分析,定义了空间数据立方体地理空间维、专题维和时间维分别包含的数据种类和内容,设计了它们的维和维层次数据结构;表述了维构成空间数据立方体的方法;确定了维的多维数组组织及存储策略;描述了空间度量的聚集概念,结合具体的图例讲述了点状、线状、面状空间度量的聚集过程。  相似文献   

11.
空间分析动态建模技术   总被引:1,自引:0,他引:1  
业务系统开发过程中,为解决采用传统开发模式的专业空间分析模型与模型算法紧耦合而导致的复杂建模过程和难以有效复用的问题,本文提出一种空间分析动态建模技术,提出功能聚合的过程是空间信息模型实例化的过程:利用形式化语言和工作流建模规范构建业务规则,基于图论构建模型逻辑图的形式化转换规则,完成规则绑定;提出权限资源绑定模型,完成资源绑定。选取深圳市肾综合征出血热地理因素相关性定性分析专业模型验证空间分析动态建模技术的可行性。  相似文献   

12.
The East Kolkata Wetlands is a unique resource recovery system. The Ramsar Convention recognized it as a ‘Wetland of International Importance’ in August 2002. However, the long-term resource exploitation and land use changes in the dynamic ecosystem have resulted in non-linear environmental responses. This is an attempt using open source remote sensing datasets to capture the spatio-temporal transformation of the wetland resulting from various anthropogenic activities. Landsat MSS and TM imageries of 1973, 1980, 1989, 2001 and 2010 were classified using Maximum Likelihood Classifier to monitor the wetland change; however, to study wetland dynamics, the post-classification wetland change detection maps have been generated for two temporal phases, i.e. 1973–1989 and 1989–2010. This study finds that the area under wetlands has reduced comprehensively in the past 40 years due to the conversion of wetlands into various other uses such as urban expansion of the Kolkata metropolitan city.  相似文献   

13.
针对GIS数据与计算机辅助设计(CAD)数据之间的差异性,以及现有转换方法存在的问题,该文提出了一种计算机辅助设计数据处理方法——采用空间数据操作引擎(FME)和Arc Map联合使用的方法。该方法能够较好地解决计算机辅助设计数据向GIS数据转换的难题,实现了对计算机辅助设计数据的批量转换和处理。以某市的地形图为数据源进行实例论证,实验结果显示运用该文所提方法能够更好地处理计算机辅助设计数据,为计算机辅助设计地形图的转换提供了可行的方案;特别是对转换出来的数据进行了拓扑重建、附属性值以及多边形数据分类处理,能够更好地保持数据的精度和完整性,更有利于数据的入库。  相似文献   

14.
15.
In recent decades, there is an increasing need for harmonised and accurate information on the status and extent of forests. However, delineating the extent of forest areas is a complex task, since the existence of more than 100 definitions of forest worldwide causes considerable discrepancies in forested area estimates. The aim of this work was to examine the potential of geographic object based image analysis (GEOBIA) and very high spatial resolution imagery to discriminate forest areas following two different definitions of forest in northern Greece. In particular, we examined the definition of forest under the Greek law as well as the United Nations Food and Agricultural Organisation definition. Our findings suggest that the developed GEOBIA approach not only performed remarkably well for the discrimination of forest areas but also allowed to estimate rapidly and reliably forest extents when the two aforementioned forest definitions were employed.  相似文献   

16.
史云飞  贺彪 《测绘科学》2013,38(2):12-14,21
本文提出了一种适于表达三维地籍的空间拓扑数据模型,并分别在概念层次和实现层次给出了概念模型和逻辑模型。概念模型分为3层:要素层、几何层和拓扑层。要素层用于表述地籍管理对象,几何层用于描述实体的几何形态,拓扑层用于表达实体间的拓扑关系。在概念模型基础上,给出了对应的逻辑模型。实验结果表明:所提出的模型有效、可行。  相似文献   

17.
The existing indicators related to spatial association, especially the K function, can measure only the same dimension of vector data, such as points, lines and polygons, respectively. We develop four new indicators that can analyze and model spatial association for the mixture of different dimensions of vector data, such as lines and points, points and polygons, lines and polygons. The four indicators can measure the spatial association between points and polygons from both global and local perspectives. We also apply the presented methods to investigate the association of temples and villages on land-use change at multiple distance scales in the Guoluo Tibetan Autonomous Prefecture in Qinghai Province, PR China. Global indicators show that temples are positively associated with land-use change at large spatial distances (e.g., >6000 m), while the association between villages and land-use change is insignificant at all distance scales. Thus temples, as religious and cultural centers, have a stronger association with land-use change than the places where people live. However, local indicators show that these associations vary significantly in different sub-areas of the study region. Furthermore, the association of temples with land-use change is also dependent on the specific type of land-use change. The case study demonstrates that the presented indicators are powerful tools for analyzing the spatial association between points and polygons.  相似文献   

18.
围绕GIS应用系统在空间数据分析效率提升的方面,本文提出了一套基于分布式自动化并行处理框架的效率提升方法,阐述了如何基于ArcPy、WebAPI、分布式调度、调度控制因子等关键技术,实现分布式自动化并行处理。本文方法有助于便捷、高效地解决大量空间数据分析处理的效率问题。  相似文献   

19.
Abstract

A significant Geographic Information Science (GIS) issue is closely related to spatial autocorrelation, a burning question in the phase of information extraction from the statistical analysis of georeferenced data. At present, spatial autocorrelation presents two types of measures: continuous and discrete. Is it possible to use Moran's I and the Moran scatterplot with continuous data? Is it possible to use the same methodology with discrete data? A particular and cumbersome problem is the choice of the spatial-neighborhood matrix (W) for points data. This paper addresses these issues by introducing the concept of covariogram contiguity, where each weight is based on the variogram model for that particular dataset: (1) the variogram, whose range equals the distance with the highest Moran I value, defines the weights for points separated by less than the estimated range and (2) weights equal zero for points widely separated from the variogram range considered. After the W matrix is computed, the Moran location scatterplot is created in an iterative process. In accordance with various lag distances, Moran's I is presented as a good search factor for the optimal neighborhood area. Uncertainty/transition regions are also emphasized. At the same time, a new Exploratory Spatial Data Analysis (ESDA) tool is developed, the Moran variance scatterplot, since the conventional Moran scatterplot is not sensitive to neighbor variance. This computer-mapping framework allows the study of spatial patterns, outliers, changeover areas, and trends in an ESDA process. All these tools were implemented in a free web e-Learning program for quantitative geographers called SAKWeb© (or, in the near future, myGeooffice.org).  相似文献   

20.
杨慧  慈慧  孙亚琴 《测绘科学》2011,36(5):237-239
本文在简介“空间分析与建模”教学概况的基础上,分析了高校进行“空间分析与建模”教学的教学目标,通过指导学生参加高校GIS技能竞赛,结合竞赛依托平台进行技能与技巧的培训和指导,并将参赛实践引入到“空间分析与建模”的课程教学中,使得教学与竞赛相结合,促进了“空间分析与建模”教学的改革,使该课程教学始终与全国性学生竞赛实践紧...  相似文献   

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