Logical data modelling for geographical applications

Abstract.

A formal, yet practical, GeoRelational Data Model (GRDM) is presented for the logical database design phase of the development of spatial information systems. Geographic applications are viewed in the context of information systems development. The generic needs of modelling spatial data are analyzed; it is concluded that they are not served satisfactorily by existing data models, so specifications of modelling tools for spatial application design are given. GRDM provides a set of representational constructs (relations and layers for the logical schema; virtual layers, object classes and spatial constraints for the user views) on top of well-established models. It constitutes part of a full, easily automated application design methodology. Extensive examples demonstrate the relevance, and ease-of-use of the platform-independent GRDM.     

Taxonomy for surveying the use and value of geographical information!

Abstract

Understanding the use and value of geographical information in decision making has been identified as crucial to the further development of geographical information systems and related spatial analysis techniques. Research into the use of geographical information will be through surveys and case studies. A taxonomy for investigating the use of geographical information and its associated value is needed to structure the surveys and case studies. This paper presents an initial attempt at such a taxonomy, intended to support continuing research into the use and value of geographical information. The survey methodology to be supported will be mostly telephone and/or mail questionnaires, and this has influenced the structure of the taxonomy. The goal of this work is to create a taxonomy suitable for use in surveys that will enhance the understanding of the use and value of geographical information in decision making.     

Research Paper. The predictive use of GIS to model property valuations

Abstract

GIS is a technology which is ideally suited to analysis of the market values of properties, since such values are based upon spatial comparisons as well as individual property attributes. Great Britain now has a new mechanism of local taxation, the council tax, which is based upon the capital values of properties. Central to the implementation of this tax has been the potentially controversial assignment of properties to valuation ‘bands’. This paper posits that a geographical model embedded within a GIS provides an alternative means of devising credible capital values, and anticipates some of the prospects for the use of GIS in local revenue-raising.     

Geographical object–oriented databases—a case study

ABSTRACT

An Australian standard for Spatial Data Transfer modelled on the draft American standard is likely to be introduced in 1993. The spatial data model is not accommodated by existing DBMS such as relational systems. Using this model as an example, the suitability of object–oriented database systems for geographical databases is demonstrated. Some initial performance figures obtained with the ONTOS system on an example database are given.     

Efficiently implementable algebra for distributed in-network spatial analysis

Existing sensor network query processors (SNQPs) have demonstrated that in-network processing is an effective and efficient means of interacting with wireless sensor networks (WSNs) for data collection tasks. Inspired by these findings, this article investigates the question as to whether spatial analysis over WSNs can be built upon established distributed query processing techniques, but, here, emphasis is on the spatial aspects of sensed data, which are not adequately addressed in the existing SNQPs. By spatial analysis, we mean the ability to detect topological relationships between spatially referenced entities (e.g. whether mist intersects a vineyard or is disjoint from it) and to derive representations grounded on such relationships (e.g. the geometrical extent of that part of a vineyard that is covered by mist). To support the efficient representation, querying and manipulation of spatial data, we use an algebraic approach. We revisit a previously proposed centralized spatial algebra comprising a set of spatial data types and a comprehensive collection of operations. We have redefined and re-conceptualized the algebra for distributed evaluation and shown that it can be efficiently implemented for in-network execution. This article provides rigorous, formal definitions of the spatial data types, points, lines and regions, together with spatial-valued and topological operations over them. The article shows how the algebra can be used to characterize complex and expressive topological relationships between spatial entities and spatial phenomena that, due to their dynamic, evolving nature, cannot be represented a priori.     

Fundamental operations in computer-assisted map analysis

Abstract

Geographical information systems (GIS) provide capabilities for the mapping, management and analysis of cartographic information. Unlike most other disciplines, GIS technology was born from specialized applications. A comprehensive theory relating the various techniques used in these applications is only now emerging. By organizing the set of analytic methods into a mathematical structure, a generalized framework for cartographic modelling is developed. Within this framework, users logically order primitive operators on map variables in a manner analogous to traditional algebra and statistics. This paper describes the fundamental classes of operations used in computer-assisted map analysis. Several of the procedures are demonstrated using a fourth-generation computer language for personal computers.     

Research related to geographical information systems at the Natural Environment Research Council's Unit for Thematic Information Systems

Abstract

The wide variety of research into aspects of geographical information systems (GIS) undertaken at the Natural Environment Research Council's Unit for Thematic Information Systems is described. This includes work on spatial data models, on the application of artificial intelligence to improve the quality of input of remotely-sensed data, on automation of map cataloguing, on improving display and on GIS modelling.     

A review of temporal database research and its use in GIS applications

Abstract

A great deal of recent work in computer science applies itself to temporal database design. Designers of geographical information systems (GIS) can build on this work to create a temporal GIS capability to trace geographical change and understand geographical processes. This paper reviews temporal research in information processing, contrasts various proposed temporal database designs and summarizes the problems of adapting it to GIS requirements.     

Modelling alpine permafrost distribution,Val de Rechy,Valais Alps (Switzerland)

The spatial distribution of the alpine permafrost is modelled in the uppermost part of Val de Rechy (Valais Alps, Switzerland) with the use of a geographical information system (GIS). Two empirical-statistical models are compared and their validity tested by a set of bottom temperature of winter snow (BTS) measurements carried out in the field. One model can simulate the spatial distribution of the permafrost facing ground warming consecutive to climatic change. Local/regional maps of simulated permafrost distribution as presented in this paper can be useful in the context of a preventive approach for natural hazards management.     

A spatial analytical perspective on geographical information systems

Abstract

The field of geographical information systems (GIS) is reviewed from the viewpoint of spatial analysis which is the key component of the familiar four-part model of input, storage, analysis and output Input is constrained by the limits of manual methods and problems of ambiguity in scanning. The potential for developments in output is seen to be limited to the query mode of GIS operation, and to depend on abandoning the cartographic model. Discussion of storage methods is organized around the raster versus vector debate and the need to represent two spatial dimensions in one. A taxonomy of GIS spatial analysis operations is presented together with a generic data model. Prospects for implementation are discussed and seen to depend on appropriate scales of organization in national and international academic research.     

Mapping uncertain geographical attributes: incorporating robustness into choropleth classification design

ABSTRACT

Choropleth mapping provides a simple but effective visual presentation of geographical data. Traditional choropleth mapping methods assume that data to be displayed are certain. This may not be true for many real-world problems. For example, attributes generated based on surveys may contain sampling and non-sampling error, and results generated using statistical inferences often come with a certain level of uncertainty. In recent years, several studies have incorporated uncertain geographical attributes into choropleth mapping with a primary focus on identifying the most homogeneous classes. However, no studies have yet accounted for the possibility that an areal unit might be placed in a wrong class due to data uncertainty. This paper addresses this issue by proposing a robustness measure and incorporating it into the optimal design of choropleth maps. In particular, this study proposes a discretization method to solve the new optimization problem along with a novel theoretical bound to evaluate solution quality. The new approach is applied to map the American Community Survey data. Test results suggest a tradeoff between within-class homogeneity and robustness. The study provides an important perspective on addressing data uncertainty in choropleth map design and offers a new approach for spatial analysts and decision-makers to incorporate robustness into the mapmaking process.     

“面向区域”的GIS控件的设计与使用

本文提出了一个“面向区域”GIS控件的概念———即以特定的地理区域为对象,将基础地理信息连同有关的GIS功能操作融合为一个可重用的程序模块,以Microsoft的COM(即“组件对象模型”)技术为基础,组织为“GIS化”的ActiveX控件。这种GIS控件,将面向对象技术中的“对象”扩展到了整个特定的地理区域空间,其核心思想是不仅封装了GIS的数据模型,必要的功能操作,而且封装了所有的基础地理信息。由于省去了对空间数据的处理,因而这种GIS控件可被广大非GIS专业的信息系统开发者灵活、简便地用于各种管理信息系统、办公自动化系统和决策支持系统的GIS功能扩充,也可用于构建一般的地理信息系统,因而有利于GIS技术应用的普及。文章最后给出了有关陕西省的应用实例     

Migration as Spatial Interaction

Abstract

The migration process is presented through the use of a movement model. The model described is a heuristic device that can be used by (1) teachers to point out the salient factors involved in migration, or (2) by researchers as a guide to theory formulation. The behavioral aspects of the decision to migrate are discussed in a spatial interaction framework. Numerous research efforts are put in a logical geographical structure for classroom presentation.     

Spatial analysis of linguistic data with GIS functions

Abstract

During the 1980s techniques for analysis of geographical patterns have been refined to the point that they may be applied to data from many fields. Quantitative spatial analysis and existing functions available in geographical information systems (GIS) enable computerized implementations of these spatial analysis methods. This paper describes the application of quantitative spatial analysis and GIS functions to analysis of language data, using the extensive files of the Linguistic Atlas of the Middle and South Atlantic States (LAMSAS). A brief review of recent development of using quantitative and statistical methods for analysing linguistic data is also included.     

Visualizing Alternative Models and their Objective Functions in the Solution of Optimal Location Problems

Abstract

This paper presents an argument for introducing location-allocation theory to advanced undergraduate and beginning graduate students in a simplified continuous space environment that is relatively free of the distorting effects of networks and other aspects of more differentiated “real-world” environments. This approach can enable instructors to reinforce visually the role of different models and their objective functions. In this simplified setting, students can initially concentrate on the link between these mathematical programming techniques and the spatial nature of the problems being solved. In a short time, students can move into more advanced methods in more differentiated environments. A freeware program entitled NEWLAP was developed to facilitate this approach. This software features a variety of spatial allocation models and their associated constraints that can be applied on both the plane and the sphere. This paper outlines how this software can be used to show alternative solutions using different models on the same data set as well as application of the software in a “real world” problem on a global scale.     

Regional Urbanization,Spatial Justice,and Place

Revisiting work such as Edward Soja's Postmetropolis reminds us of the importance of a geographical perspective, as well as a thoroughly process oriented and dynamic consideration of the urban. Soja's work emphasizes multi-scalar processes that work to produce urbanization, and the complex, fragmented, and unequal spaces that result. Attention to spatial process and justice is essential, but is incomplete without consideration and real attention to the material and geographically embedded experiences of place that manifest urbanization in everyday life.     

Establishing a geographical information system in relation to its use A process of strategic choices†

Abstract

The planning and establishment of a geographical information system (GIS) relates to its context and intended use. GIS are a specialized type of information system, typically dealing with spatial data. This paper explores the environment of an envisaged GIS; the information utilization system and the wider object system. The planning and design of a GIS go beyond technical issues; they also have to take behavioural and organizational aspects of the utilization of information into account and contribute to a process of organizational development The paper is in two parts. The first (§ 2) explores salient aspects in the planning and design process, the second ( § 3) suggests some guidance in this task. The suggested approach of strategic choice in planning and establishing a GIS is designed to cope with the prevailing uncertainties in this planning process. It distinguishes between those decisions which have to be taken at once and choices which may be left open for the future.     

Spatial interpolation using conditional generative adversarial neural networks

ABSTRACT

Spatial interpolation is a traditional geostatistical operation that aims at predicting the attribute values of unobserved locations given a sample of data defined on point supports. However, the continuity and heterogeneity underlying spatial data are too complex to be approximated by classic statistical models. Deep learning models, especially the idea of conditional generative adversarial networks (CGANs), provide us with a perspective for formalizing spatial interpolation as a conditional generative task. In this article, we design a novel deep learning architecture named conditional encoder-decoder generative adversarial neural networks (CEDGANs) for spatial interpolation, therein combining the encoder-decoder structure with adversarial learning to capture deep representations of sampled spatial data and their interactions with local structural patterns. A case study on elevations in China demonstrates the ability of our model to achieve outstanding interpolation results compared to benchmark methods. Further experiments uncover the learned spatial knowledge in the model’s hidden layers and test the potential to generalize our adversarial interpolation idea across domains. This work is an endeavor to investigate deep spatial knowledge using artificial intelligence. The proposed model can benefit practical scenarios and enlighten future research in various geographical applications related to spatial prediction.