一种基于属性水平版本结构的时空数据模型

以属性水平版本结构为理论基础,在空间数据表中,面状地物类表和线状地物类表是有效时间(Tv)和数据库时间(Td)的载体,事务时间反映版本创建时间(Tc),并将结点和弧段的版本改变记录到它们所属的面状地物类表中;属性数据表中,区分记录属性的连续变化与不连续变化。数据模型既体现了版本信息和时间要素,又减少了数据冗余。     

时空信息云平台下数据管理及可视化方法

针对智慧城市时空信息云平台中海量时空数据的管理和可视化问题,该文提出了一种时空索引建立及时空数据可视化方法。时空索引机制将时间、空间与专题属性作为同等重要的维度,兼顾了三者的查询效率,实现对时空数据的快速有效提取。时空数据可视化表达方法提出了时间轴动画、多时态对比、对象状态回溯等可视化方式,实现时空数据的动态交互式表达。该方法在"智慧常州时空信息云平台"项目中进行了实现,证明这种时空数据组织管理方法可较高效地实现数据的检索调度,且具有较强的可操作性;基于此的时空数据可视化方法亦具备较佳的时空对象动态表达效果。     

中国公路差分GPS测量

本文讨论使用差分GPS进行道路测量数据采集中遇到的几个重要问题。外业数据采集主要解决了GPS道路观测数据、地物属性数据以及匹配时间数据的获取的问题 ;内业数据处理解决了如何用差分GPS方法获得满足要求的道路矢量数据 ;地物属性匹配解决了矢量数据和属性数据之间的融合 ,获得可以直接入库的基础数据     

基于快照-增量的时空索引机制研究

已有的时空索引是基于时间或空间索引的扩展,将相应的空间或时间成分作为属性,难以同时顾及时间查询和空间查询的效率.分析基于版本-增量的时空数据模型,提出基于快照-增量的时空数据索引机制.该索引将时间和空间作为同等重要的维,满足时空联合查询的效率.     

气象GIS中的气象时态数据模型的设计

根据气象数据的空间位置少量变化、属性数据变化频繁的时空变化特征,提出了一种基于时间的简单对象模型——属性与空间、时间关联扩展的气象时态数据模型,并在气象GIS平台中实现数据模型的实例化,实现了对气象时态数据的管理。     

时空数据模型的N1NF关系基础

Ｎ１ＮＦ关系方法在处理非表格化的复杂结构对象时优于传统关系方法，因而适合于时态ＧＩＳ。本文讨论了空间对象的Ｎ１ＮＦ表达和操作，将空间，时间和属性结合为一个整体，与作者的前期工作一起构成了矢量式时空数据模型的Ｎ１ＮＦ关系基础；本文还初步讨论了建立在这个基础上的面状地理要素的时空数据模型。     

时空数据的可视化表达研究

多维动态数据的可视化表达是地图与GIS学科面临的一个重要问题,按照时空地物的几何类型结合专题地图的各种表示方法相对系统地论述了时空数据的可视化表达方法。应用快照式和增量式两种可视化方法可视化动态地形图数据,两种方法相比,增量式具有更大的优点。     

物流配送时空信息可视化方法改进

现代物流配送过程要求高效、易监督、低成本地运转,时空信息的可视化在此过程中发挥着重要作用。在分析了现有物流信息可视化方法的基础上,基于时间思想与GIS可视化,对物流时空信息的三维显示进行了改进。该方法将空间位置匹配到二维电子地图上,将时间作为第3轴展现在三维可视化环境中,属性信息以文字标注的方式出现,实现了物流配送过程中时间、空间和属性信息的集成显示。在ArcGIS软件平台上开发了原型系统对该方法进行了实现。该方法的应用能提升现有物流管理系统在时空信息一体化显示方面的效果,使管理人员、承运人和货主对配送线路、送达时间、商品属性变更等有更为清晰直观的了解,便于对整个配送过程进行监督、分析和管理。     

专题地图属性信息的LOD表达与TreeMap可视化

提出一种面向专题地图属性信息的LOD可视化方法,应用新型层次结构信息可视化工具TreeMap实现了属性信息的多层次展示,随着专题地图尺度变化自适应调节属性信息的结构层次细节。并将面域拓扑制图技术Cartogram与之结合,建立了顾及区域拓扑特征的多层次属性信息空间定位方法,为受众提供了面向属性信息的跨层次空间认知策略。     

地球科学相关论文摘要

030 30 1　GIS中面元的误差熵模型 /李大军 (武汉大学 )… / /测绘学报 .- 2 0 0 3,32 ( 1) .- 31～ 35根据整个线元边缘分布的平均信息熵确定了“ε -带”的宽度 ,提出了线元的平均误差熵带模型 ,进一步扩展到面元的误差熵环模型 ,误差熵环的带宽取构成边界线的各线段误差熵的加权平均值 ,通过算例进行了比较 ,并绘出了其可视化图形。0 30 30 2　GIS属性数据精度的缺陷率度量的统计模型 /刘春(香港理工大学 )… / /测绘学报 .- 2 0 0 3,32 ( 1) .36～ 41基于抽样检验在测量数据精度分析中的思想 ,提出基于抽样的缺陷率方法 ,对GIS属性…     

Temporal Interpolation of Spatially Dynamic Polygons

In this study we compare two methods of interpolating simple metrics from polygons that change over time. Conventional methodology involves computing values of the metrics at points in time where the polygon is observed, and interpolating between these observed values to estimate values at other points in time. An alternative method applies interpolation techniques to the locations of vertices composing polygons are interpolated between observations and metrics are computed from the interpolated polygon shapes. We conducted a Monte Carlo simulation of both techniques using simulated polygons composed of varying numbers of vertices, which were allowed to move randomly over varying numbers of discrete time periods. We observed differences in the success of the two methods when applied to three metrics: Area, Perimeter, and Area/Perimeter Ratio. We found the two techniques to perform differently depending upon the metric being interpolated. Full results are presented and possible reasons why the techniques succeeded or failed under various conditions are discussed.     

时态信息可视化模型研究及实现

时间问题是地理学中一个基本的研究问题。随着空间技术和现代信息基础设施的飞速发展,使得空间信息具备了较强的时态特性,传统静态地图中的可视化表达方式已无法满足时态信息的动态表示需求,如何在空间格局上和基于时间维的动态演化过程中,提供时态信息模拟结果的可视化分析和表达,是不可忽缺的一个环节。针对当前时空数据模型较多,而可视化研究相对较少的现状,在充分研究时态信息特点的基础上,研究了可视化动态过程所涉及的相关模型,包括概念模型、时空耦合模型以及预测模型等。     

STAMP: spatial–temporal analysis of moving polygons

Research questions regarding temporal change in spatial patterns are increasingly common in geographical analysis. In this research, we explore and extend an approach to the spatial–temporal analysis of polygons that are spatially distinct and experience discrete changes though time. We present five new movement events for describing spatial processes: displacement, convergence, divergence, fragmentation and concentration. Spatial–temporal measures of events for size and direction are presented for two time periods, and multiple time periods. Size change metrics are based on area overlaps and a modified cone-based model is used for calculating polygon directional relationships. Quantitative directional measures are used to develop application specific metrics, such as an estimation of the concentration parameter for a von Mises distribution, and the directional rate of spread. The utility of the STAMP methods are demonstrated by a case study on the spread of a wildfire in northwestern Montana.      

利用透明度进行时空信息可视化

利用电子地图中透明度视觉变量产生的虚实感,在对当前焦点时刻时空内容进行完全表达的同时,以不同透明度图形对时间上下文中的内容进行辅助表达,实现兼顾焦点时刻和时间上下文的时空可视化。该方法能够从时间全局上描绘时空对象的时间分布和时态关系,帮助把握时空发展的趋势和规律,同时更加高效地利用地图幅面,时空信息量更加丰富。     

卫星时态信息可视化技术研究

时间问题是地理学中一个基本的研究问题,针对当前时空数据模型较多,而可视化研究相对较少的现状,总结、探讨了时态信息可视化所需要的插值、动画、交互等相关技术,重点研究了当前我国卫星影像实时获取能力不能满足用户较高时间分辨率分析的情况,提出了相应的改进方法,探索了时空尺度与分辨率的匹配与可视化表达方法、多目标时间协调等问题,并在影像数据的基础上,实现了时态信息的动态显示。     

时间序列空间数据可视化中有关问题的研究

就土地利用变化可视化这一实例 ,对时间序列空间数据可视化的图形关系分析和图形内插等问题进行了深入的研究 ,得出了土地利用变化中图形关系变化的四种基本形式 ,并针对这四种基本图形的变化情形研究出了相应的内插策略 ;在对现有的图形内插算法研究的基础上 ,提出了基于物理场模型的整体内插算法 ,该算法能够较好地解决文中的图形内插问题。     

Recent Literature

Development of a temporal geographic information system (GIS) and spatio-temporal data modeling are key to incorporating time into geographic information science. This paper describes how to design and develop temporal GIS that will work with spatio-temporal data represented in various data models, and it introduces a prototype temporal GIS with a case study. In temporal GIS, the integration of multiple spatio-temporal representations is based on common spatial and temporal reference systems. In other words, a map window of temporal GIS visualizes spatio-temporal data valid at the same time within one spatial area. To achieve such visualization, separate data editing and query modules are required for each spatio-temporal data model (STDM). In the temporal query interface, after a user specifies a time, the system automatically hires correspondent modules to retrieve spatio-temporal data valid at that time. Besides temporal queries common to all STDMs, each module may provide additional temporal query capabilities specific to that STDM. In the case study, I implement a prototype temporal GIS for three STDMs. The examples of query and visualization, which use three datasets (census data, land use/land cover, and elevation data) demonstrate the prototype temporal GIS can integrate multiple temporal representations.     

Implementation of novel polygon-based obfuscation methods to improve privacy of agricultural data

Geoprivacy protection is a significant concern when sharing data. To support sustainable land management by leveraging existing agricultural data, research is needed to identify how the polygon nature of static field parcels can be obfuscated to allow data sharing among individuals and organizations. In this study, five adaptive polygon-based obfuscation methods including PN*Rand, PDonut-k, PDensity-k, PAHilb, and PDonut_AHilb methods were developed and applied on the Irish Nutrient Management Planning Online (NMP Online) agricultural dataset. The polygon-based obfuscation methods introduced in this study were designed with the consideration of properties of spatial polygon objects including the spatial coordinates, shape and size of the polygon, topology, and spatial relationship between adjacent polygons that can be used to identify real-world objects. These methods were developed to guarantee that there is no false-identification and non-unique obfuscation which is important for static polygon objects in terms of accuracy and privacy protection. Qualitative approaches were developed to identify the optimal values of inner and outer radii of donut shape based on k-anonymity satisfaction and subsequently obtain the optimal value of k-anonymity. Several evaluation methods were implemented to compare the methods performance. Density-based methods particularly PDonut-AHilb provide the best trade-off between field parcel confidentiality and spatial pattern preservation and should be considered for researchers and practitioners obfuscating polygon data.     

建筑物白模多边形的自动合并

建筑物白模多边形数据可广泛应用于许多领域,但在实际应用中,由于数据太过细致,且目前使用的建筑物白模多边形数据存在拓扑关系错误,不满足生产要求,这给地图综合中建筑物群的自动合并提出了新的要求。因此提出了一种基于约束性Delaunay三角网的建筑物白模多边形自动合并方法,在保持建筑物整体结构和视觉效果的前提下减少不必要的细节。该方法能够消除原始建筑物图形数据中的空间拓扑关系错误,并对建筑物白模多边形进行一致性处理,有利于独栋整体建筑物的三维可视化。并用C#编程语言开发桌面应用程序对该方法进行了实现,通过和ArcGIS建筑物综合工具的建筑物群合并结果进行对比分析,验证了该方法的有效性和实用性。     

Modeling Dynamic Polygon Objects in Space and Time: A New Graph-based Technique

The analysis of dynamic spatial systems requires an explicit spatio-temporal data model and spatio-temporal analysis tools. Event-based models have been developed to analyze discrete change in continuous and feature-based spatial data. In this paper, a spatio-temporal graph model is described that supports the analysis of continuous change in feature-based polygon spatial data. The spatio-temporal graph edges, called temporal links, track changes in polygon topology through space and time. The model also introduces the concept of a spatial-interaction region that extends a model's focus beyond short-term local events to encompass long-term regional events. The structure of the spatio-temporal graph is used to classify these events into five types of local polygon events and two types of spatial-interaction region events. To illustrate its utility, the model is applied to the ecological question of how patch size influences longevity in underwater plant communities in Chesapeake Bay, USA. Both a short-term local analysis and a longer-term regional analysis showed that patches of plants, or groups of patches, larger than one to two hectares in size were more likely to persist than smaller patches or groups of patches. Overall, the spatio-temporal graph model approach appears applicable to a variety of spatio-temporal questions.