共查询到19条相似文献，搜索用时 156 毫秒
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三维地理信息系统中几何特征的误差模型 总被引：1，自引：0，他引：1
史文中 《武汉大学学报(信息科学版)》1998,(1)
本文提出了三维地理信息系统中几何特征的误差模型。基于面表示的三维ＧＩＳ的特征被分为点、线段及线,该模型给出这些特征的一种误差描述,即围绕着这些几何特征的量测值的一个范围。 相似文献
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GIS系统集成的模型基础 总被引：1，自引：0，他引：1
为满足各行各业的不同要求，ＧＩＳ与其它系统的集成已成为一个引人注目的问题，一般说，系统的集成就是要融合各组成部分的优点以满足用户的特殊要求。ＧＩＳ系统集成研究的一个重要方面就是模型基础，因为各系统所用的模型不同，如ＧＩＳ模型中缺少环境模型所必需的时——空结构，ＧＩＳ系统一般用“面向特征的模型”，遥感数据处理一般用“域模型”，而这些建模方法在整个系统的数据处理、数据表示和数据分析中是十分重要的，它对于认识那些由特殊模型引起的特殊问题也是十分有用的，因此本文以３级模式（外模式、概念模式和内模式）描述了ＧＩＳ和其它系统，这种方法使各种集成问题归于各组成部分的相应模式。 相似文献
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面向对象的GIS结构设计 总被引：3，自引：0，他引：3
本文提出了一种以地理实体为中心加空间数据结构模型－面向对象的ＧＩＳ结构模型。在此基础上，讨论了利用规范关系存贮ＧＩＳ中的各种基本数据，以及用ＮＦ２（Ｎｏｎ－ＦｉｒｓｔＮｏｒｍａｌ－Ｆｏｒｍ）的嵌套结构描述和构造面向对象的几何数据，从而实现了面向对象的ＧＩＳ结构设计与管理，提高了ＧＩＳ系统的生命力，简化了系统的开发进程。 相似文献
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为了有效地实现ＧＩＳ分析中地形数据的可视化，本文提出了分形内插与Ｄｅｌａｕｎａｙ三角网结合的三维地形可视化数据模型。该模型不仅能满足几何精度，保持地形特征，而且具有表面质感理想的可视化效果。该模型的空间分辨率可以由尺度、位置和时间参量来调节，具有多尺度表达、局部加密表达和时空动态表达的特点。该模型适于ＧＩＳ的可视化操作与分析。 相似文献
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数据模型是描述数据内容及其相互关系的工具，它是数据库设计的核心问题之一。空间数据相对于一般事务性数据具有数据量大和更加复杂的特点，因此，地理信息系统（ＧＩＳ）中空间数据模型的研究显得尤为重要。商业化的ＧＩＳ一般采用关系数据模型，而关系数据模型缺乏表达空间实体及其相互关系的能力，因此形成了图形库与属性库相分离的ＧＩＳ系统结构。这种结构不便于空间实体的整体管理。为解决这一问题，人们探索了扩展的关系模型和面向对象的数据模型。本文介绍了这三种ＧＩＳ数据模型及其与之对应的三种系统结构，分析了这些模型与系统结构的优越性和不足之处，并揭示了数据模型与系统结构之间的内在关系。 相似文献
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分布式GIS分层体系结构模型的研究 总被引：12，自引：0，他引：12
提出了一个通用的分布式ＧＩＳ的分层体系结构模型;用户界面层、应用层、应用接口层和数据服务层,给出了该模型的思想和主要特征,并结合Ｉｎｔｅｒｎｅｔ／Ｉｎｔｒａｎｅｔ环境讨论了模型的实现方法。分层分布式ＧＩＳ模型的提出可以部分地解决现有的Ｉｎｔｅｒｎｅｔ／Ｉｎｔｒａｎｅｔ ＧＩＳ存在的问题。 相似文献
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虚拟GIS—GIS和科学可视化的集成 总被引：1，自引：0，他引：1
本文叙述了科学可视化技术和地理信息系统（ＧＩＳ）结合的必要性,介绍了当前这方面的研究现状,引入了虚拟ＧＩＳ这一概念,提出了一个虚拟ＧＩＳ的概略模型,并说明了虚拟ＧＩＳ与互联网络的关系。 相似文献
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GIS的数据组织与处理方法 总被引：10，自引：0，他引：10
《测绘通报》1994,(1)
ＧＩＳ的数据组织与处理方法李德仁，龚健雅，边馥苓地理信息系统（ＧＩＳ）与其他一些处理日常事务的信息系统如银行管理系统、图书检索系统不同。地理数据必须包括位置、可能的拓扑关系、地物的特征等，数据相当复杂。因此，人们为ＧＩＳ中的数据结构和数据模型进行了大... 相似文献
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研究了通过扫描数字化试验，获取了GIS中特征点对点误差的基础数据，分析了误差的成因，讨论了误差的分布规律和统计特性，为扫描数字化精度控制及数据质量的评价提供了参考依据。 相似文献
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Eryong Liu 《制图学和地理信息科学》2016,43(4):321-327
This article presents a new development in measuring the positional error of line features in Geographic Information Systems (GIS), in the form of a new measure for estimating the average error variance of line features, including line segment, polyline, polygon, and curved lines. This average error measure is represented in the form of a covariance matrix derived by an analytical approach. Corresponding error indicators are derived from this matrix. The error of line features mainly results from two factors: (1) an error propagated from the original component points of line features and (2) a model error of interpolation between these points. In this study, a method of average error estimation has been derived regarding the first type error of line features that are interpolated by either linear or cubic interpolation methods. The main contribution of the research is the provision of an error measure to assess the quality of spatial data in application settings. The proposed error models for estimating average error variance of line features in a GIS are illustrated by both simulated and practical experiments. The results show that the line accuracy from a linear interpolation is better than a line interpolated using a cubic model. 相似文献
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Modelling Positional Uncertainty of Line Features by Accounting for Stochastic Deviations from Straight Line Segments 总被引：1，自引：0，他引：1
Sytze de Bruin 《Transactions in GIS》2008,12(2):165-177
The assessment of positional uncertainty in line and area features is often based on uncertainty in the coordinates of their elementary vertices which are assumed to be connected by straight lines. Such an approach disregards uncertainty caused by sampling and approximation of a curvilinear feature by a sequence of straight line segments. In this article, a method is proposed that also allows for the latter type of uncertainty by modelling random rectangular deviations from the conventional straight line segments. Using the model on a dense network of sub‐vertices, the contribution of uncertainty due to approximation is emphasised; the sampling effect can be assessed by applying it on a small set of randomly inserted sub‐vertices. A case study demonstrates a feasible way of parameterisation based on assumptions of joint normal distributions for positional errors of the vertices and the rectangular deviations and a uniform distribution of missed sub‐vertices along line segments. Depending on the magnitudes of the different sources of uncertainty, not accounting for potential deviations from straight line segments may drastically underestimate the positional uncertainty of line features. 相似文献
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Laser scanning systems have been established as leading tools for the collection of high density three-dimensional data over physical surfaces. The collected point cloud does not provide semantic information about the characteristics of the scanned surfaces. Therefore, different processing techniques have been developed for the extraction of useful information from this data which could be applied for diverse civil, industrial, and military applications. Planar and linear/cylindrical features are among the most important primitive information to be extracted from laser scanning data, especially those collected in urban areas. This paper introduces a new approach for the identification, parameterization, and segmentation of these features from laser scanning data while considering the internal characteristics of the utilized point cloud – i.e., local point density variation and noise level in the dataset. In the first step of this approach, a Principal Component Analysis of the local neighborhood of individual points is implemented to identify the points that belong to planar and linear/cylindrical features and select their appropriate representation model. For the detected planar features, the segmentation attributes are then computed through an adaptive cylinder neighborhood definition. Two clustering approaches are then introduced to segment and extract individual planar features in the reconstructed parameter domain. For the linear/cylindrical features, their directional and positional parameters are utilized as the segmentation attributes. A sequential clustering technique is proposed to isolate the points which belong to individual linear/cylindrical features through directional and positional attribute subspaces. Experimental results from simulated and real datasets demonstrate the feasibility of the proposed approach for the extraction of planar and linear/cylindrical features from laser scanning data. 相似文献
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Analytical Modelling of Positional and Thematic Uncertainties in the Integration of Remote Sensing and Geographical Information Systems 总被引：1，自引：0，他引：1
This paper describes three aspects of uncertainty in geographical information systems (GIS) and remote sensing. First, the positional uncertainty of an area object in a GIS is discussed as a function of positional uncertainties of line segments and boundary line features. Second, the thematic uncertainty of a classified remote sensing image is described using the probability vectors from a maximum likelihood classification. Third, the "S-band" model is used to quantify uncertainties after combining GIS and remote sensing data. 相似文献
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从概率论的角度构造了矢量ＧＩＳ中线要素的定位不确定性模型，并根据讨论问题的需要，给出了衡量点、线定位误差的精度指标。这一研究可为ＧＩＳ产品的质量估计提供有效依据。 相似文献