A Technique for Building Representation in Oblique View Maps of Modern Urban Areas

Abstract

This paper presents a technique for creating oblique view maps of urban areas. We identify and apply cartographic and cognitive principles to develop a solution in the context of state-of-art geographic information systems. The gap in the ability of these systems to render three-dimensional buildings into maps is addressed. At the core of our solution is a building facade modelling approach that supports varying degrees of abstraction. This is achieved by introducing a concept of 'facade waveforms' and representing building facades as combinations of these waveforms. A Fourier series approximation of the waveforms is used during the rendering processes resulting in an elegant solution to anti-aliasing. The formulation retains the semantic information in the representation that enables meaningful extensions like night time facade generation. The solution is implemented as a pixel shader and therefore leads to a large reduction in texture memory requirement compared with existing building rendering techniques. Additionally, in the case of web based systems, there is significant reduction in bandwidth requirement. We highlight the features of the proposed solution by generating demonstrative maps and images.     

Interpolation of Point Values From Isoline Maps

A Bidirectional Hermitian Spline (BHS) method for the estimation of point values from isoline maps is presented and compared to three other methods. Hermitian splines are used and first derivatives are estimated by either Akima's method or by a clamped cubic spline, if Akima's method returns a zero first derivative. Every desired point value is interpolated twice, once by each of two orthogonally-directed splines. The two spline estimates are then averaged using the error formula for Hermitian splines. In addition, a periodic Hermitian spline is constructed around the study-area perimeter (representing a cross-sectional profile of the edge) to damp undesirable edge effects. Point values can be estimated from small-scale isoline maps drawn in spherical coordinates or from large-scale isoline maps drawn in Cartesian coordinates.     

Exploratory Analysis of Spatial Data Using Interactive Maps and Data Mining

We present new methods for analyzing geo-referenced statistical data. These methods combine visualization and direct manipulation techniques of exploratory data analysis and algorithms for data mining. The methods have been implemented by integrating two hitherto separate software tools: Descartes for interactive thematic mapping, and the data mining toolbox Kepler. In using these tools, data analysis may proceed as a steady interaction between visual inspiration and insights gained from mathematical–statistical calculations. After introducing the various components of the methods and tools, the paper guides the reader through in-depth examples of using the tools in the context of analysis of urban demographic data. In particular, it is shown how geography-based classifications of urban districts can be related to available thematic characteristics by applying the data mining algorithms classification tree derivation, attribute weighting, and subgroup discovery.     

Visual Abstraction and Stylisation of Maps

Abstract

We explore visual map abstraction for the generation of stylized renderings of 2D map data. We employ techniques that are centred around the concept of shape simplification and graph layout and that allow iterative abstraction of 2D maps. We use data from publicly available sources and show how we can iteratively generate aesthetic renditions of these maps. These renditions do not have the goal to allow for navigation tasks, but instead show the map data in a distorted manner. The techniques used to create these images apply simplification, abstraction/generalisation, and displacement operations to the map elements in varying orders and add stylistic shading to produce aesthetic renditions for print or electronic displays. The degree of abstraction/generalisation can be individually chosen and determines the characteristics of the distorted map: whether components retain their shape, degenerate, or are processed in a manner that the abstraction becomes the focus of the image rather than the underlying map data. The renditions can be further personalized by choosing shading and colours for this shading. Together, the presented techniques allow for playful and creative exploration of aesthetic renditions of 2D map data.     

Integrating Sketch Maps with GIS to Explore Fear of Crime in the Urban Environment: A Review of the Past and Prospects for the Future

Understanding the spatial dimension of fear of crime in the urban environment is important to understanding behaviors in response to this concern. Making this connection between perception and action has long been a goal of scholars in the social and health sciences, though this complex relationship has yet to be fully elucidated. Specifically, in studies on fear of crime and its influence on behavior, a variety of definitions and methods have been employed. This situation has yielded insights, as well as inconsistencies. In the past decade, Geographic Information Systems (GIS) has been added to this methodological mix, though it too has contributed limited understanding of the environmental perception-behavior nexus. During this time, some scholars have integrated a traditional technique for accessing environmental perception, the sketch map, with this newer technology. This article provides a review and critical assessment of the way GIS has been used to understand fear of crime, specifically through the integration of sketch maps. This focus is framed by an overview of substantive and methodological concerns and concludes with a discussion of continued research needs. As behavioral responses to fear of crime are acknowledged to impact physical and mental health and overall well-being, in addition to the viability of neighborhoods, research in this area will continue apace. However, for integration of sketch maps in GIS to be a valuable methodological contributor to this line of inquiry, users of the approach must understand its complexities. This article outlines these issues so that they may be considered in future research and may improve the ability for this approach to yield new understanding of fear of crime.     

Assessment of Shuttle Radar Topography Mission Elevation Data Based on Topographic Maps in Turkey

Depending on scale, topographic maps depicting the shape of the land surfaces of the Earth are produced from different data sources. National topographic maps at a scale of 1:25 000 (25K maps) produced by General Command of Mapping are used as the base map set in Turkey. This map set, which consists of approximately 5500 sheets, covers the whole country and is produced using photogrammetric methods. Digital Elevation Models (DEMs) created from these maps are also available. Recently, another data source, Synthetic Aperture Radar (SAR) interferometric data, has become more important than those produced by conventional methods. The Shuttle Radar Topography Mission (SRTM) contains elevation data with 3 arc-second resolution and 16 m absolute height error (90 percent confidence level). These data are freely available via the Internet for approximately 80 percent of the Earth's land mass. In this study, SRTM DEM was compared with DEM derived from 25K topographic maps for different parts of Turkey. The study areas, each covering four neighboring 25K maps, and having an area of approximately 600 km², were chosen to represent various terrain characteristics. For the comparison, DEMs created from the 25K maps were obtained and organized as files for each map sheet in vector format, containing the digitized contour lines. From these data, DEMs in the resolution of 3 arc-second were created (25K-DEM), in the same structure as the SRTM DEM, allowing the 25K-DEMs and the SRTM DEM to be compared directly. The results show that the agreement of SRTM DEM to the 25K-DEM is within about 13 m, which is less than the SRTM's targeted error of 16 m. The spatial distribution of the height differences between SRTM-DEM and the 25K-DEM and correlation analysis show that the differences were mainly related to the topography of the test areas. In some areas, local height shifts were determined.     

分区统计地图上符号的视觉搜寻和认知工效研究

根据某地区的分区统计数据和有关图集,总结设计出4种方案的分区统计地图,在自行编制的认知测试软件上进行了目标搜寻测试。结果表明,在分区统计地图上搜寻目标时,视觉系统运用了平行加工策略和序列加工策略,4个方案的目标搜寻平均反应时间和正确率受到这两种策略的影响。     

绘制透视立体图的一种方法

本文对利用以规则格网表示的地面数字高程模型绘制透视立体图的方法进行了讨论,以透视原理为基础计算出模型点对应的变换点坐标。在分析过去采用的单方向处理隐藏线的方法基础上,提出了双方向处理隐藏线的方法,并应用该方法绘制出了透视立体图。     

A GIS Approach to Exploring Monetary Value on Enclosure Era Property-Related Maps

Historical enclosure era property-related maps can tell us a great deal about the life and times of communities in the past. This study offers a unique approach to studying the historical landscape by applying GIS techniques to the examination of an eighteenth-century English village. Using novel GIS applications relying on historical maps, the study explores various aspects of the village’s physical and social characteristics. In doing so, the study forges effective linkages between cultural and landscape variables to reveal aspects of the historical landscape in eighteenth-century Britain previously inaccessible to researchers. This, in turn, provides a much more comprehensive and sophisticated template for future use by historical geographers in a number of contexts.     

Bicomponent Trend Maps: A Multivariate Approach to Visualizing Geographic Time Series

The most straightforward approaches to temporal mapping cannot effectively illustrate all potentially significant aspects of spatio-temporal patterns across many regions and times. This paper introduces an alternative approach, bicomponent trend mapping, which employs a combination of principal component analysis and bivariate choropleth mapping to illustrate two distinct dimensions of long-term trend variations. The approach also employs a bicomponent trend matrix, a graphic that illustrates an array of typical trend types corresponding to different combinations of scores on two principal components. This matrix is useful not only as a legend for bicomponent trend maps but also as a general means of visualizing principal components. To demonstrate and assess the new approach, the paper focuses on the task of illustrating population trends from 1950 to 2000 in census tracts throughout major U.S. urban cores. In a single static display, bicomponent trend mapping is not able to depict as wide a variety of trend properties as some other multivariate mapping approaches, but it can make relationships among trend classes easier to interpret, and it offers some unique flexibility in classification that could be particularly useful in an interactive data exploration environment.     

地图数学定义的研究

在地图内容和形式数学表示的基础上研究了地图的数学定义。由于引入隐式地图和变换条件,故所有储存地图信息的载体均可属于地图的范围,从而使地图定义获得了广义的解释和精确的表达。     

高分辨率卫星遥感数据在城市地图更新中的应用

城市地图是全面反映城市发展和城市社会经济现象的综合信息载体,是城市基础空间数据库和城市GIS的重要组成部分。文章就高分辨率卫星遥感数据在城市地图更新中的工艺、生产平台、影像纠正、影像融合、地图更新的方法及应用进行了探讨。     

灾害保障图可视化表达规律探究

探讨了灾害保障图的研究现状,基于"区域灾害系统"理论,给出了灾害保障图较为翔实的定义和分类,并着重从表达内容、表示方法、表现形式和符号设计方面对其可视化表达规律进行了探究。     

GIS技术在景观视觉分析中的应用

探索应用地理信息系统空间分析技术,通过三维数字高程模型修正模拟规划在建大型建筑群的“地形”表面,并对观察点和目标点之间视觉的通视、可视域分析,采用定性和定量相结合的方法,形象直观分析评价未来重庆科技馆的景观视觉效果,     

基于Google Maps的车辆监控系统关键技术研究

介绍了基于WebGIS的车辆监控系统关键技术,讨论了基于Google Maps构建车辆监控系统的优越性,利用Google Maps和Ajax实现了车辆定位,位置查询,轨迹回放,异步数据通信等关键技术。     

基于纸质地图的单像地形图快速数字修测系统

提出了一种基于纸质地形图的单像地形图数字修测方法,它能在不具有矢量地形图的地区,根据新摄取的航摄像片直接对原有的地形图分版图的扫描影像进行修测,然后用绘图输出修测后的像素地图,或用于ＧＩＳ中相应数据的更新。     

Auto CAD技术在市政工程系列图成图上的应用

本文通过对ＡｕｔｏＣＡＤ技术的二次开发，实现了市政工程系列图图形的直观显示、编码管理、快速成图等功能。     

一种城市公交线网分布的可视化分析方法

可视化分析技术在分析交通数据、发现交通问题及辅助决策扮演着越来越重要的角色,成为一项重要的智能交通技术。为了更加直观地展示城市公交线网空间分布的疏密情况,本文基于北京市公交线路矢量数据,采用直接可视化和聚集可视化两种方法对公交线网的空间分布进行了分析。通过对原数据处理计算得到了基于北京市主干道的公交线路分布数据并进行了直接可视化;同时利用HTML5的Canvas绘制热力图的方法对原数据进行了聚集可视化,根据可视化结果对北京市公交线路空间分布情况进行了分析。该方法对城市公交线网规划和优化有实用价值和意义。     

MAPGIS二次开发软件Section和Excel软件在编绘矿业权设置方案图件的交互应用与探讨

在矿业权设置方案中,矿业权现状图及矿业权设置平面图分别是一定区域内矿业权现状分布和矿业权设置方案的直观体现。本文详细介绍MAPGIS二次开发软件Section和Microsoft Office Excel软件在编辑制作该类图件的交互应用和体会。