Relationship of uncertainty between polygon segment and line segment for spatial data in GIS

The mathematic theory for uncertainty model of line segment are summed up to achieve a general conception, and the line error band model of ?σ is a basic uncertainty model that can depict the line accuracy and quality efficiently while the model of ?m and error entropy can be regarded as the supplement of it. The error band model will reflect and describe the influence of line uncertainty on polygon uncertainty. Therefore, the statistical characteristic of the line error is studied deeply by analyzing the probability that the line error falls into a certain range. Moreover, the theory accordance is achieved in the selecting the error buffer for line feature and the error indicator. The relationship of the accuracy of area for a polygon with the error loop for a polygon boundary is deduced and computed.     

Relationship of Uncertainty Between Polygon Segment and Line Segment for Spatial Data in GIS

The mathematic theory for uncertainty model of line segment are summed up to achieve a general conception, and the line error band model of εp is a basic uncertainty model that can depict the line accuracy and quality efficiently while the model of εm and error entropy can be regarded as the supplement of it. The error band model will reflect and describe the influence of line uncertainty on polygon uncertainty. Therefore, the statistical characteristic of the line error is studied deeply by analyzing the probability that the line error falls into a certain range. Moreover, the theory accordance is achieved in the selecting the error buffer for line feature and the error indicator, The relationship of the accuracy of area for a polygon with the error loop for a polygon boundary is deduced and computed.     

GIS空间数据几何变换的不确定性传播

针对点位误差、线元在对称、旋转变换过程中不确定性的传播规律,该文采用误差椭圆和εm模型描述GIS空间数据对象模型中最常用的点、线元素的误差域,讨论几何变换(如对称、旋转变换)过程中不确定性的积累和传播规律,结合区间算法给出了变换后误差域模型。基于区间运算的INTLAB模拟结果验证了该模型的有效性和实用性。研究结果对进一步探讨其他几何变换过程中不确定性的积累传播规律具有一定参考。     

GIS空间数据面元与线元不确定性的关系

通过对线元误差落在一定区域内的概率分析,进一步明确了线元误差的概率统计性质,对多边形面积精度与面元误差环对面积精度影响这两者关系进行推导和数值计算,探讨多边形面积的标准差和面元误差带面积之间的关系,通过对多边形各边的线元误差分析,进一步描述多边形面积误差的分布状况和概率统计性质。     

人口地理数据的不确定性及其对策研究

从第五次人口普查建立人口地理信息系统的实践出发 ,对人口地理数据的不确定性进行了归纳和总结。人口地理数据的不确定性主要包括空间地理数据的不确定性、人口数据的不确定性和系统对人口地理数据处理和分析时引入的不确定性。在对各种类型的不确定性进行分析的同时 ,针对数据的不确定性存在的客观事实 ,探讨了在建立和应用人口地理信息系统时应注意的问题、采取的措施和策略     

空间知识挖掘的自然面群聚集度聚类方法

空间聚类是挖掘空间知识的重要手段之一.针对现有方法难以处理几何、分布特征差异大的面群聚类问题,本文提出了一种面要素分布密度的描述参数—聚集度,并设计了一种自然面群聚类方法.首先,分析了面要素分布密度的影响因子,定义了聚集度的概念,设计其计算方法并验证其有效性及优势;然后,基于聚集度和边界最短距离建立相邻面从属关系,识别...     

GIS中线元的误差熵带研究

基于现有的线元位置不确定性模型大多与置信水平的选取有关,而置信水平的选取带有一定程度的主观性,因而不能惟一确定。引入信息熵理论,提出了线元的误差熵带模型,并将它与"E-带"进行了比较,计算了落入其内的概率。该模型根据联合熵惟一确定,与置信水平的选取无关。     

General entropy model of line segments uncertainty in GIS

Spatial data uncertainty can directly affect the quality of digital products and GIS-based decision making. On the basis of the characteristics of randomicity of positional data and fuzziness of attribute data, taking entropy as a measure, the stochastic entropy model of positional data uncertainty and fuzzy entropy model of attribute data uncertainty are proposed. As both randomicity and fuzziness usually simultaneously exist in linear segments, their omnibus effects are also investigated and quantified. A novel uncertainty measure, general entropy, is presented. The general entropy can be used as a uniform measure to quantify the total uncertainty caused by stochastic uncertainty and fuzzy uncertainty in GIS.     

空间数据模糊聚类的有效性(英文)

The validity measurement of fuzzy clustering is a key problem. If clustering is formed, it needs a kind of machine to verify its validity. To make mining more accountable, comprehensible and with a usable spatial pattern, it is necessary to first detect whether the data set has a clustered structure or not before clustering. This paper discusses a detection method for clustered patterns and a fuzzy clustering algorithm, and studies the validity function of the result produced by fuzzy clustering based on two aspects, which reflect the uncertainty of classification during fuzzy partition and spatial location features of spatial data, and proposes a new validity function of fuzzy clustering for spatial data. The experimental result indicates that the new validity function can accurately measure the validity of the results of fuzzy clustering. Especially, for the result of fuzzy clustering of spatial data, it is robust and its classification result is better when compared to other indices.     

空间线要素综合算法的不确定性讨论

简述了几种曲线综合算法思路,从综合算法阈值的计算,综合算例数据等方面对综合算法及其不确定性进行了量化的评价,并进一步总结了综合算法不确定的各种表现.     

空间数据研究的发展及对策

随着地理信息科学和地理信息系统的发展,空间数据先后经历数据生产、数据质量、数据不确定性和可用性4个研究阶段。在分析各阶段研究内容和方法的基础上,深入分析空间数据现有研究间的联系与区别,并给出未来的研究对策。     

A new approach to simulate positional error of line segment in GIS

To determine the distribution of positional error of a line segment, Monte Carlo approach is applied to simulate the probability density function of a line segment with the assumption that the error of endpoints in a line segment follows a two-dimensional normal distribution. For such purpose, a stochastic generator used for uncertain endpoints with the two-dimensional normal distribution is presented. This forms the basis of the generation of random line segment for the simulation of the error model of a whole line segment. The error models cover the cases where two endpoints are either independent or dependent to each other, also including a special case that the distance between two random endpoints in a line segment is close enough.     

无缝GIS的空间数据组织研究

提出了"无缝GIS"这一全新概念,指出数据组织是无缝GIS实选择方案和海量无缝空间数据组织方法.     

基于席尔宾斯基垫片的GIS矢量数据置乱方法

为提高GIS矢量数据在数据传输过程中的隐蔽性,该文结合分形模型席尔宾斯基垫片变换技术,通过对要素点集合中每个点的位置进行置乱处理,实现了一种针对GIS线面图层数据的置乱方法,并基于置乱度的置乱效果评价方法,明确了置乱效果与分形维数之间的正相关关系。实验表明:该方法保持了有效的数据格式和整体形态的相似性,具有较好的隐蔽性和迷惑性;在满足处理效率和隐蔽性应用需求的前提下,可有效保障矢量地理数据在数据传输、数据托管服务、封装存储中的安全性。     

PDA环境下的地下管网GIS数据结构的研究

为了改变传统的地下管线外业调查流程,将探查和测量合为一步,实现数据采集的数字化,降低管线外业调查的复杂度,本文提出了将PDA用于地下管线外业调查的研究思路。文章首先介绍了PDA用于管线外业调查的优势,然后针对PDA的特点和地下管线专业要求,设计了一种适用于PDA环境下的地下管网GIS数据结构,最后使用上海外高桥区域管线数据进行了验证,结果系统运行稳定,数据处理迅速,界面显示清晰,实践证明该数据结构较好地达到了系统要求。     

测量误差与测量不确定度表述方法的研究

研究了国家计量技术规范－－《测量不确定度评定与表示》（JJF1059－1999）与测量数据处理的误差理论的区别与联系。讨论了如何依照JJF1059－1999的规定，完整、准确地评价和描述测量结果。     

GIS中三维空间直线的误差熵模型

从信息熵的角度提出了三维空间直线的误差熵模型，该模型由以垂直直线的平面误差熵为半径的圆柱体和两端点的误差球组成，是一种完全确定的度量空间线元不确定性的模型。理论分析与实验表明，本文所提出的模型具有较好的效果。     

Subdivision of polygon parcel in land-use data generalization

In land-use data generalization, the removal of insignificant parcel with small size is the most frequently used operator. Traditionally for the generalization method, the small parcel is assigned completely to one of its neighbors. This study tries to improve the generalization by separating the insignificant parcel into parts around the weighted skeleton and assigning these parts to different neighbors. The distribution of the weighted skeleton depends on the compatibility between the removed object and its neighbor, which considers not only topological relationship but also distance relationship and semantic similarity. This process is based on the Delaunay triangulation model. This paper gives the detailed geometric algorithms for this operation.     

Subdivision of polygon parcel in land-use data generalization

In land-use data general-ization, the removal of insignificant parcel with small size is the most fre-quently used operator. Traditionally for the generalization method, the small parcel is assigned completely to one of its neighbors. This study tries to improve the generalization by sepa-rating the insignificant parcel into parts around the weighted skeleton and assigning these parts to different neighbors. The distribution of the weighted skeleton depends on the com-patibility between the removed object and its neighbor, which considers not only topological relationship but also distance relationship and semantic sim-ilarity. This process is based on the Delaunay triangulation model. This paper gives the detailed geometric al-gorithms for this operation.