The Nature of Uncertainty in Historical Geographic Information

While the presence of uncertainty in the geometric and attribute aspects of geographic information is well known, it is also present in temporal information. In spatiotemporal GIS databases and other formal representations, uncertainty in all three aspects of geography (space, time, and theme) must often be modeled, but a good data model must first be based on a sound theoretical understanding of spatiotemporal uncertainty. The nature of both uncertainty inherent in a phenomenon (often termed indeterminacy) and uncertainty in assertions of that phenomenon can be better understood through the Uncertain Temporal Entity Model , which characterizes the cause, type, and form of uncertainties in the spatial, temporal, and attribute aspects of geographic information. These uncertainties are the result of complexities and problems in two processes: the process of conceptualization, by which humans make sense of an infinitely complex reality, and measurement, by which we create formal representations (e.g. GIS) of those conceptual models of reality. Based on this framework, the nature and form of uncertainty is remarkably consistent across various situations, and is approximately equivalent in the three aspects, which will enable consistent solutions for representation and processing of spatiotemporal data.     

Specifying the transformations within and between geographic data models

Geographic information is acquired according to several different underlying models of geographic space. Any meaning inherent within a dataset is intrinsically connected to the model by which it was captured. A design is presented for an integrated geographic information system offering a number of distinct views onto geographic space, of varying degrees of abstraction, to support the needs of an expanded user base. An architecture for such a system is developed by an extension of the traditional three layer architecture used in database design. The movement of data from one level of abstraction to another is formalized by a series of dataset and model transformations operating between four different geographic data models. From this formalism, a functional taxonomy of GIS operations is developed.     

GIS conceptual data model

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GIS conceptual data model

In order to set up a conceptual data model that reflects the real world as accurately as possible, this paper firstly reviews and analyzes the disadvantages of previous conceptual data models used by traditional GIS in simulating geographic space, gives a new explanation to geographic space and analyzes its various essential characteristics. Finally, this paper proposes several detailed key points for designing a new type of GIS data model and gives a simple holistic GIS data model.     

基于GML的GIS语义共享实现途径的探讨

GIS技术下的地理信息共享表现为GIS数据共享,在研究GIS数据共享时,是以最终实现地理信息共享为目的的。为达到这一目的,首先必须解决数据本身的共享问题,其次要解决数据所表达的语义的共享问题。探讨了构建基于GML(Geography Markup Language)的顾及语义的空间数据交换标准,并利用这一标准进行数据转换从而实现GIS语义共享。     

CAD数据到EPS数据的转换实践

随着地理信息技术的发展及实际应用需求的不断扩大,GIS软件也得到了空前的发展,越来越多的单位和个人开始关注GIS数据的生产、应用和共享。EPS2008地理信息工作站是清华山维公司推出的一款优秀的GIS软件产品,EPS平台综合了CAD技术与GIS技术,实现从数字图到信息化的转变。本文主要从数据转换的角度出发,通过对CAD数据和EPS数据结构进行深入分析、研究的基础上,论证了基于清华山维EPS地理信息平台软件跨平台转换的可行性、技术方法和工作准备,并通过实际案例,讨论了采用该方法实施数据转换的效果及特点。     

Assessing Similarity of Geographic Processes and Events

The increased availability of spatiotemporal data collected from satellite imagery and other remote sensors provides opportunities for enhanced analysis of geographic phenomena. Much of the new data includes regular snapshots of the environment. Comparison of these snapshots can provide information about changes to the phenomena of interest. However, conventional GIS data models and analytical tools lack capabilities to adequately handle massive multidimensional data. One of the fundamental tools necessary to meet such challenges is query support to retrieve and summarize data according to dynamic geographic phenomena, such as geographic events and processes, of interest. Such query support depends upon abilities to assess spatiotemporal similarity so that data representing geographic events that exhibit the spatiotemporal characteristics of interest can be identified in a GIS database. To this end, this paper introduces a method to assess similarity of geographic events and processes (such as storms) based on their spatiotemporal characteristics (such as distribution of precipitation). We developed six indices to capture static and dynamic characteristics of geographic events and applied the Dynamic Time Warping method to temporal sequences of the six indices to examine the similarity among these events. With a case study, we demonstrated the proposed indices and method capable of comparing spatiotemporal characteristics of events as recorded in a GIS database and categorizing spatiotemporal data into groups of events according to their behavior in space and time.     

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     

Representing Complex Geographic Phenomena in GIS

Conventionally, spatial data models have been designed according to object- or field-based conceptualizations of reality. Conceptualization of complex geographic phenomena that have both object- and field-like properties, such as wildfire and precipitation, has not yet been incorporated into GIS data models. To this end, a new conceptual framework is proposed in this research for organizing data about such complex geographic phenomena in a GIS as a hierarchy of events, processes, and states. In this framework, discrete objects are used to show how events and processes progress in space and time, and fields are used to model how states of geographic themes vary in a space-time frame. Precipitation is used to demonstrate the construction and application of the proposed framework with digital precipitation data from April 15 to May 22, 1998, for the state of Oklahoma, U.S.A. With the proposed framework, two sets of algorithms have been developed. One set automatically assembles precipitation events and processes from the data and stores the precipitation data in the hierarchy of events, processes, and states, so that attributes about events, processes, and states are readily available for information query. The other set of algorithms computes information about the spatio-temporal behavior and interaction of events and processes. The proposed approach greatly enhances support for complex spatio-temporal queries on the behavior and relationships of events and processes.     

RS与GIS一体化数据结构的研究

详细阐述了RS与GIS一体化的概念 ,通过对RS与GIS一体化方面的研究与分析 ,进一步明确RS与GIS一体化对空间数据存储结构的要求 ,着重探讨了几种典型的用于RS与GIS一体化的数据结构 ,针对现有数据结构存在的问题与不足 ,提出了一种具有普遍适用价值的基于语义网络的空间数据存储结构 ,并给出一个应用实例     

基于时态的地理信息系统控件的开发与应用

介绍了时态地理信息的由来及发展现状,分析了时态GIS的概念、功能和各种模型.介绍了如何实现普通GIS向时态GIS的转化,并通过实例展示了时态GIS的应用.     

面向上海城市数字化转型的新型测绘

城市数字化转型、“科学化、精细化、智能化”的城市治理、“新基建”的落地和数字经济的发展都迫切需要空间地理数据向“全域、全息、全空间、多维、高频”推进,实现物理空间的数字孪生。本文结合上海市城市数字化转型对地理信息的新需求,从空天地数据获取手段、全息空间数据内涵、二三维一体的成果形式、泛在测绘更新方法和按需组装服务方式等方面提出了构建以基于地理实体的智能化全息测绘为核心的新型测绘体系,形成了城市数字化转型地理信息新服务的解决方案。     

A Review and Evaluation of Uncertainty Classification and the Error‐Band Geometry Model

Advances in computer technologies have improved the quality of maps, making map comparison and analysis easier, but uncertainty and error still exist in GIS when overlaying geographic data with multiple or unknown confidence levels. The goals of this research are to review current geospatial uncertainty literature, present the Error‐Band Geometry Model (EBGM) for classifying the size and shape of spatial confidence intervals for vector GIS data, and to analyze the interpretability of the model by looking at how people use metadata to classify the uncertainty of geographic objects. The results from this research are positive and provide important insight into how people interpret maps and geographic data. They suggest that uncertainty is more easily interpreted for well defined point data and GPS data. When data is poorly defined, people are unable to determine an approach to model uncertainty and generate error‐bands. There is potential for using the EBGM to aid in the development of a GIS tool that can help individuals parameterize and model spatial confidence intervals, but more research is needed to refine the process by which people use the decision tree. A series of guiding questions or an “uncertainty wizard” tool that helps one select an uncertainty modeling approach might improve the way people apply this model to real‐world applications.     

浅谈分布式数据库在地理信息系统中的应用

随着人类科学技术的飞速发展,信息革命推进了各个学科的共同发展,使许多学科的发展由单一化到多元化,并逐渐形成交叉学科。就地理信息系统而言,多种交叉学科通过各种信息资源构成了它的框架,各种数据组成了它的主体。同时,由于数据量的不断扩大以及地域分布的不断扩散,使得基于网络环境下的分布式数据库得到了前所未有的发展。     

GIS中地理边线不一致性的处理

地理边线的不一致性是GIS多源空间数据集成、建库和分析中的常见问题。首先分析了地理边线不一致性的类型,并归结为顶点数目完全和不完全匹配两种情况,其中前者可以直接利用结点广义捕捉算法处理。为了匹配后者的顶点数目,提出了投影配点的标准化处理,并导出了投影点的坐标计算和误差估计公式。此外,还导出了一致化改正后地理边线长度的误差估计公式。最后通过算例说明所提出方法的实现过程。     

Fields as a framework for integrating GIS and environmental process models. Part 1: Representing spatial continuity

Linking a GIS to a spatially distributed, physically-based environmental model offers many advantages. However, the implementation of such linkages is generally problematic. Many problems arise because the relationship between the reality being represented by the mathematical model and the data model used to organize the spatial data in the GIS has not been rigorously defined. In particular, while many environmental models are based on theories that assume continuity and incorporate physical fields as independent variables, current GISs can only represent continuous phenomena in a variety of discrete data models. This paper outlines a strategy in which field variables are used to enable modellers to work directly with the spatial data as spatially continuous phenomena. This allows the manner in which the spatial data has been discretized and the ways in which it can be manipulated to be treated independently from the conceptual modelling of physical processes. Modellers can express their spatial data needs as representations of reality, rather than as elements of a GIS database, and a GIS-independent language for model development may result. By providing a formal linkage between the various models of spatial phenomena, a mechanism is created for the explicit expression of transformation rules between the different spatial data models stored and manipulated by a GIS.     

论军事地图学与地理信息工程的发展

本文包括3个部分.第一部分,从10个方面简要总结了军事地图学与地理信息工程科学技术60年来的主要成就,并从7个方面分析了推动地图学与地理信息工程科学技术进步与发展的理论与技术;第二部分,从7个方面论述了地图学与地理信息工程科学技术的发展趋势;第三部分,提出了未来要重点研究的10个领域,包括空间认知理论、空间数据自动综合理论与方法、多维动态空间信息可视化、空间信息网格、空间数据挖掘与知识发现、空间数据不确定性与数据质量控制、多智能化代理技术及其应用、嵌入式GIS技术等.     

论军事地图学与地理信息工程的发展

本文包括3个部分。第一部分,从10个方面简要总结了军事地图学与地理信息工程科学技术60年来的主要成就,并从7个方面分析了推动地图学与地理信息工程科学技术进步与发展的理论与技术;第二部分,从7个方面论述了地图学与地理信息工程科学技术的发展趋势;第三部分,提出了未来要重点研究的10个领域,包括空间认知理论、空间数据自动综合理论与方法、多维动态空间信息可视化、空间信息网格、空间数据挖掘与知识发现、空间数据不确定性与数据质量控制、多智能化代理技术及其应用、嵌入式GIS技术等。     

Use of a Three-Domain Repesentation to Enhance GIS Support for Complex Spatiotemporal Queries

As the development of Geographic Information Systems (GIS) proceeds to advanced scientific and societal applications, there is an emerging need to enhance GIS support for complex spatiotemporal queries. Dynamic GIS representations (as opposed to static, map-based representations) that can integrate proper data elements in the production of geographic information are required. This paper demonstrates the use of a three-domain representation that facilitates compilation of higher-level information (such as frequency and rate) from preliminary data records (such as time and location) stored in a database. The three-domain representation is compared with snapshot, space-time composite, and spatiotemporal object models using a sample data set for forest transitions. While the three-domain representation is a normalization of these data models, it offers a conceptual alternative that enables GIS to represent spatiotemporal behaviors of geographic entities, in addition to entities as well as histories at locations as emphasized in most GIS data models. The comparison shows that the three-domain representation has combined the strengths of the space-time composite and spatiotemporal object models. Moreover, it enables aggregations of analytical use along with dynamic mappings between geographic concepts and locations, a distinct capability that takes GIS query processing beyond the level of information support offered by static map-based data models.