GIS and simple systems for visual,interactive, spatial analysis

Abstract

In much the same way as a spreadsheet is more appropriate to some needs than a fully relational DBMS, many users interested in analysis of spatially referenced data have fairly unsophisticated requirements for extensive data storage or complex retrieval functions, and limited needs for topographic detail, cartographic accuracy or advanced map editing; however, they do require access to a wide range of statistical functions for data transformation, reduction and smoothing, multivariate analysis, and the modelling of spatial relationships. This paper argues that the needs of such users are poorly met by the 'mainstream' model for GIS that is often presented in the literature. A PC-based system, equivalent in GIS terms to the spreadsheet, is described. It integrates simple data structures, limited map creation and editing, a powerful range of standard and spatially orientated statistical functions, and the ability to interactively present results through chloropleth, contour, proportionate symbol, or proximally shaded maps. It is particularly designed to be easily accessible and to encourage visual interactive analysis. For some users such a system has acted as an adequate solution in its own right and for others it has provided a useful educational transition to more extensive and powerful systems.     

An Experimental Performance Evaluation of Spatio-Temporal Join Strategies

Many applications capture, or make use of, spatial data that changes over time. This requirement for effective and efficient spatio‐temporal data management has given rise to a range of research activities relating to spatio‐temporal data management. Such work has sought to understand, for example, the requirements of different categories of application, and the modelling facilities that are most effective for these applications. However, at present, there are few systems with fully integrated support for spatio‐temporal data, and thus developers must often construct custom solutions for their applications. Developers of both bespoke solutions and of generic spatio‐temporal platforms will often need to support the fusion of large spatio‐temporal data sets. Supporting such requests in a database setting involves the use of join operations with both spatial and temporal conditions – spatio‐temporal joins. However, there has been little work to date on spatio‐temporal join algorithms or their evaluation. This paper presents an evaluation of several approaches to the implementation of spatio‐temporal joins that build upon widely available indexing techniques. The evaluation explores how several algorithms perform for databases with different spatial and temporal characteristics, with a view to helping developers of generic infrastructures or custom solutions in the selection and development of appropriate spatio‐temporal join strategies.     

Geocoding Recommender: An Algorithm to Recommend Optimal Online Geocoding Services for Applications

Today, many services that can geocode addresses are available to domain scientists and researchers, software developers, and end‐users. For a number of reasons, including quality of reference database and interpolation technique, a given address geocoded by different services does not often result in the same location. Considering that there are many widely available and accessible geocoding services and that each geocoding service may utilize a different reference database and interpolation technique, selecting a suitable geocoding service that meets the requirements of any application or user is a challenging task. This is especially true for online geocoding services which are often used as black boxes and do not provide knowledge about the reference databases and the interpolation techniques they employ. In this article, we present a geocoding recommender algorithm that can recommend optimal online geocoding services by realizing the characteristics (positional accuracy and match rate) of the services and preferences of the user and/or their application. The algorithm is simulated and analyzed using six popular online geocoding services for different address types (agricultural, commercial, industrial, residential) and preferences (match rate, positional accuracy).     

A spatial decision support system prototype for housing mobility program planning

This paper presents a GIS-based decision support system prototype intended for use by public housing authority (PHA) administrators and planners designing policy for housing mobility programs. Housing mobility programs enable low-income families, many of whom live in government-operated public housing, to move to more desirable private-market rentals via rent subsidies. Unfortunately, housing authority planners have limited ability to visualize alternative relocation schemes of cohorts of low-income families or the impacts associated with these relocation policies. Thus, they are often not able to give highest-quality advice to clients regarding places to search for private-market rental housing. Housing Location Planner assists PHA planners in three ways: it analyzes spatial, demographic and housing market characteristics of the study area, selects certain portions of the study area for input to an optimization model which generates alternative family allocations, and displays optimization model results in a way that links decision variable values and objective function values. Housing Location Planner is seen as a first step in the development of even more sophisticated multi-stakeholder spatial decision support systems for subsidized housing planning in which one or more alternative allocations of families across a study area is chosen as a basis for policy initiatives. Received: 8 September 1999/Accepted: 23 October 2000     

Possibilities of using raster data in client‐side web maps

Companies and individual developers have recently put serious effort into improving web mapping libraries. A significant front in this development is hardware‐accelerated vector graphics. Owing to those efforts, and the continuously evolving World Wide Web, users can visualize large vector layers, and even animate them. On the other hand, this rapid development cannot be observed with raster data. There are some data abstraction libraries for reading raster files, although web mapping libraries do not use them to offer raster capabilities. Since there are no mature raster management pipelines on the web, this study explores two inherently different techniques for handling raster data. One of them uses the traditional, texture‐based method. The other is a hybrid technique rendering raster layers as vectors, overcoming some limitations of the raster model. While the traditional technique gives a smooth user experience, the hybrid method shows promising results for rendering hexagonal coverages.     

British National Report to the International Cartographic Association for the Period 2011-2015

In recent years, the concepts of usability, user experience, and user-centricity have gained in interest. Digital applications, developed in line with criteria related to these approaches, ask for a deeper understanding of users and their requirements. But, even though there is a wide range of methods available, the creation of user-centric applications with good usability and user experience still poses great challenges for developers. This is also true for web maps, i.e. web map applications, which today are ubiquitous on the Internet. They have evolved into an important information and communication tool and address users who do not possess any specific knowledge of Geoinformatics (GI) or Cartography. Despite the efforts made to meet the requirements and preferences of laymen, these users still often face problems when dealing with web map applications. This refers to aspects of design, content, and functionality. Here, participatory design, which is well-known in the field of Software and Web Engineering, might provide a suitable means. By engaging users directly and actively in the application development process, developers are able to gain a profound understanding of the users and their needs. However, there are several open questions regarding the use of participatory design for designing and implementing web map applications: What does the use of participatory design in web map development processes look like in detail? How and to what degree can users be involved in the development processes? Which added values exist? These questions are addressed by the project YouthMap 5020, whose main goal it was to create a prototype youth-centric web map for the Austrian city of Salzburg (zip code 5020). Applying the approach of participatory design, about 120 teenage pupils from several local schools were involved in all kinds of tasks related to the phases of generating the youth-centric Salzburg web city map. Experience and knowledge gained thereby allowed elaborating recommendations generally useful for generating youth-centric web map applications.     

面向服务的移动GIS平台架构研究

以移动GIS平台架构为研究对象,采用面向服务思想设计并实现了一种基于"云+端"模式的移动GIS快速开发平台,提出一种分层开发模型OS-GAL-IAL,研制出跨平台、高性能、全自主的GIS内核,实现了一套精细化、流程化、可视化、易扩展的快速开发框架,能帮助开发者快速构建快速、高效的移动GIS应用系统。     

Development of a Speech-Based Augmented Reality System to Support Exploration of Cityscape

When people explore new environments they often use landmarks as reference points to help navigate and orientate themselves. This research paper examines how spatial datasets can be used to build a system for use in an urban environment which functions as a city guide, announcing Features of Interest (FoI) as they become visible to the user (not just proximal), as the user moves freely around the city. Visibility calculations for the FoIs were pre‐calculated based on a digital surface model derived from LIDAR (Light Detection and Ranging) data. The results were stored in a text‐based relational database management system (RDBMS) for rapid retrieval. All interaction between the user and the system was via a speech‐based interface, allowing the user to record and request further information on any of the announced FoI. A prototype system, called Edinburgh Augmented Reality System (EARS), was designed, implemented and field tested in order to assess the effectiveness of these ideas. The application proved to be an innovative, ‘non‐invasive’ approach to augmenting the user's reality.     

'Situating' Simulation to Model Human Spatio-Temporal Interactions: An Example Using Crime Events

Many social phenomena have a spatio‐temporal dimension and involve dynamic decisions made by individuals. In the past, researchers have often turned to geographic information systems (GIS) to model these interactions. Although GIS provide a powerful tool for examining the spatial aspects of these interactions, they are unable to model the dynamic, individual‐level interactions across time and space. In an attempt to address these issues, some researchers have begun to use simulation models. But these models rely on artificial landscapes that do not take into account the environment in which humans move and interact. This research presents the methodology for ‘situating’ simulation through the use of a new modeling tool, Agent Analyst, which integrates agent‐based modeling (ABM) and GIS. Three versions of a model of street robbery are presented to illustrate the importance of using ‘real’ data to inform agent activity spaces and movement. The successful implementation of this model demonstrates that: (1) agents can move along existing street networks; (2) land use patterns can be used to realistically distribute agent's homes and activities across a city; and (3) the incidence and pattern of street robberies is significantly different when ‘real’ data are used.     

基于Unity3D的三维虚拟地理教学系统初探

随着虚拟现实技术的发展与智能设备的普及,虚拟地理教学系统的开发与应用,得到了越来越多人的重视。Unity3D软件因其自身在虚拟现实开发方面优秀的性能,赢得了广大开发者的青睐。本文详细分析了三维虚拟地理教学系统的功能需求和不同技术平台的实现特点,结合Unity软件,在Unity平台下实现了瓦片地图金字塔模型的构建,并给出了地理视频纹理贴图的解决方案,发挥了Unity软件自身强大引擎所提供的渲染能力,验证了Unity软件对于虚拟地理系统开发的适用性。     

Providing scientific visualization for spatial data analysis: Criteria and an assessment of SAGE

A consistent theme in recent work on developing exploratory spatial data analysis (ESDA) has been the importance attached to visualization techniques, particularly following the pioneering development of packages such as SPIDER and REGARD (Haslett et al. 1990).  The focus on visual techniques is often justified in two ways: (a) the power of modern graphical interfaces means that graphics is no longer a way of simply presenting results in the form of maps or graphs, but a tool for the extraction of information from data; (b) graphical, exploratory methods are felt to be more intuitive for non-specialists to use than methods of numerical spatial statistics enabling wider participation in the process of getting data insights. However, little work has been done to decide which visualization tools might be needed to support ESDA, or how they can be most effectively implemented.  This paper briefly reviews a theoretical framework that has been suggested for addressing these issues, which comprises two elements: firstly a data model, based on the distinction between rough and smooth properties of spatial data, that defines what an analyst is looking for in data (Haining et al. 1998) and secondly a theoretical model for assessing the quality of visualisation tools (Cleveland 1994). The emphasis of this paper is the use of the theoretical framework to structure an assessment of SAGE, a software system that has been written for the spatial statistical analysis (including both exploratory and confirmatory data analysis) of area based data linked to a GIS. The aim of the assessment is to identify the desirable features of the system (that might be employed in other systems) whilst also highlighting what the additional requirements are thereby contributing to the development of systems for ESDA that contain good quality scientific visualization tools for exploratory spatial data analysis. Received: 30 September 1998/Accepted: 17 September 1999     

A vector and raster graphic mapping tool on micro-computers

Abstract

The rapid development of physically-based hydrological information and modelling systems has necessitated enhanced data entry and display systems. A 'mapping tool' is developed for the manipulation and display of spatial information, which is a cost-efficient, self-contained utility system that is suitable for use on micro-computers. It has the ability to be integrated as part of any modelling or information system. Diverse applications using the 'mapping tool' are briefly described including resource management systems for planners, mass balance studies in urban catchments and data entry systems for physically based models.     

Building Web-Based Spatial Information Solutions around Open Specifications and Open Source Software

Geographic Information Systems (GIS) are moving from isolated, standalone, monolithic, proprietary systems working in a client‐server architecture to smaller web‐based applications and components offering specific geo‐processing functionality and transparently exchanging data among them. Interoperability is at the core of this new web services model. Compliance with Open Specifications (OS) enables interoperability. Web‐GIS software's high costs, complexity and special requirements have prevented many organizations from deploying their data and geo‐processing capabilities over the World Wide Web. There are no‐cost Open Source Software (OSS) alternatives to proprietary software for operating systems, web servers, and Relational Database Management Systems. We tested the potential of the combined use of OS and OSS to create web‐based spatial information solutions. We present in detail the steps taken in creating a prototype system to support land use planning in Mexico with web‐based geo‐processing capabilities currently not present in commercial web‐GIS products. We show that the process is straightforward and accessible to a broad audience of geographic information scientists and developers. We conclude that OS and OSS allow the development of web‐based spatial information solutions that are low‐cost, simple to implement, compatible with existing information technology infrastructure, and have the potential of interoperating with other systems and applications in the future.     

Lieutenant Murdoch Mackenzie and his Survey of the Bristol Channel and the South Coast of England

Abstract

NetCDF (Network Common Data Form) is a data sharing protocol and library that is commonly used in large-scale atmospheric and environmental data archiving and modeling. The NetCDF tool described here, named NCWin and coded with Borland C + + Builder, was built as a standard executable as well as a COM (component object model) for the Microsoft Windows environment. COM is a powerful technology that enhances the reuse of applications (as components). Environmental model developers from different modeling environments, such as Python, JAVA, VISUAL FORTRAN, VISUAL BASIC, VISUAL C + +, and DELPHI, can reuse NCWin in their models to read, write and visualize NetCDF data. Some Windows applications, such as ArcGIS and Microsoft PowerPoint, can also call NCWin within the application. NCWin has three major components: 1) The data conversion part is designed to convert binary raw data to and from NetCDF data. It can process six data types (unsigned char, signed char, short, int, float, double) and three spatial data formats (BIP, BIL, BSQ); 2) The visualization part is designed for displaying grid map series (playing forward or backward) with simple map legend, and displaying temporal trend curves for data on individual map pixels; and 3) The modeling interface is designed for environmental model development by which a set of integrated NetCDF functions is provided for processing NetCDF data. To demonstrate that the NCWin can easily extend the functions of some current GIS software and the Office applications, examples of calling NCWin within ArcGIS and MS PowerPoint for showing NetCDF map animations are given.     

诱发因素影响下的滑坡参数优化预测模型研究

在降雨等外界诱发因素的综合作用下,滑坡位移预测是一个复杂的动力系统问题。利用三峡库区白家包滑坡综合监测数据,分析滑坡演化实时特征,提取影响滑坡变形的最相关因素,研究发现白家包滑坡为降雨主导型堆积层滑坡;采用自回归综合移动模型（ARIMA）模型进行拟合及预测,引入月累积降雨量对模型季节性趋势参数进行评估优化,对白家包滑坡72期月相对位移数据进行拟合及预测研究,最终模型结果和实测值的平均绝对误差和相关系数分别为2.873和0.983。研究结果表明,与传统经验法相比,优化参数模型更符合滑坡变形的一般规律。     

TERRAIN AND SURFACE MODELLING SYSTEMS: THEORY AND PRACTICE

This paper presents a critical investigation of those parts of digital mapping that relate to the specific area of terrain modelling systems. In addition, image processing and database systems are considered where they impinge on model creation or later analysis. The theoretical basis for surface mapping systems is described and an attempt is made to determine how best such systems can cover many of the practical requirements of commercial, industrial, and institutional surveyors and researchers. Some proprietary computer terrain modelling systems are mentioned where they have particular features that relate to the theme of the paper. However, most of the examples are derived from Panacea, the terrain modelling software written by the author, although in many cases any major modelling system could have been used.     

一种基于信任和角色的混合权限控制方法

本文在分析分布式大众地理信息系统中访问控制的特点,以及RBAC模型不能满足分布式系统需求的基础上,提出了基于角色和信任的混合访问控制方法:在RBAC模型的角色授权基础上,加入了用户信任度,对RBAC模型进行了有效的扩展。该方法有效解决了系统对用户分配权限后无法控制用户非法操作的弊端,并且对模型进行了实验验证。     

铁路独立坐标系的建立及坐标转换

本文以某西北某客运专线为例,论述了在铁路测量中建立独立坐标系的作用及建立这种坐标系的几种方法,并介绍了建立铁路独立坐标系所需的工程椭球构建模型,以及国家坐标系到独立坐标系的坐标转换过程,编制相应程序进行解算。     

Appreciative GIS and Strength‐Based Community Change

Problem‐solving is embedded deeply in the digital DNA of GIS. Most projects involving GIS 1.0 and 2.0 raise community weaknesses, failures and other problems and use them to motivate change. The projects often create a future that does not differ greatly from the past or last long. Although looking into community problems is important and sometimes necessary, the steps of problem‐solving do not always leave people feeling happy. To inspire communities to create change based on their strengths and achievements, and to provide better participant experience, this article develops the concept of a new form of GIS called Appreciative GIS (AGIS). AGIS are grounded in the affirmative premise that every community, however challenged, is gifted with certain assets, potentials and strengths which, when effectively exploited, can take that community to a better and sustainable future. Based on Earth's internal structure, the article develops a useful layered community model where crust, mantle and core strata represent the community's body, life‐draining and life‐giving elements in that order. The model helps explain the different views of the community from current GIS and AGIS perspectives. A Total GIS (TGIS) cube is also developed and used to indicate that current GIS commonly focus on elements of the mantle or what we do not have, what we cannot do and what makes us weak. AGIS, on the other hand, dig up the core and cultivate what we have, what we can possibly do and what makes us strong. In a significant departure from the linear approach of problem‐solving, the article suggests implementing AGIS through a 7G cyclical method. The article contends that although AGIS may not be the whole enchilada, they can serve as a beacon of hope and a powerful source of inspiration especially for individuals and groups who are perceived or made to perceive themselves as dysfunctional, weak or poor.