共查询到20条相似文献，搜索用时 109 毫秒
1.
面向"人"地学可视化中的"人".主要从地学可视化系统的使用者(简称"应用人"),从地学可视化要表达的地球表层系统地理环境中的社会人(简称"社会人").以及从作为能地理认知与思维、能表达/传递地理知识及知识创新的"人"(简称"知识人")3个方面定义.从上述3个方面建立了面向"人"的地学可视化概念框架.在面向"应用人"方面,主要介绍了协同可视化以及自我参照可视化;在面向"社会人"方面,主要阐述个体日常行为时空路径可视化、群体行为模拟可视化,以及社会关系网络可视化;在面向"知识人"方面,主要讨论知识可视化.本文最后从本体框架、信息采集与获取技术、数据组织与表达模型、可视化表达方法、主体概念方面,对于面向"人"GIS以及可视化的关键问题与技术进行了探讨. 相似文献
2.
《制图学和地理信息科学》2013,40(3):140-153
A hybrid system that integrates two-dimensional (2D) GIS and three-dimensional (3D) visualization has been developed to provide unique solutions to application domains where traditional 2D GIS and 3D visualization cannot alone provide a solution. In this paper, we focus on three key issues in realizing such an integrated system, including large-scale terrain rendering, 2D and 3D combination display (for example, rendering 2D GIS layers in 3D space), expanding traditional 2D GIS analysis functions into a 3D environment, and visualizing 3D geographical data. A generic framework is developed to integrate 3D visualization with various types of 2D GIS, such as commercial GIS software, open source GIS software and spatial databases. A prototype 2D and 3D hybrid system that seamlessly integrates 2D GIS (developed with ArcEngine) and 3D rendering engine (developed with DirectX) is then developed based on the framework. In this hybrid system, 2D and 3D data are viewed within the same scene. Multiple 2D GIS layers are overlaid on the base terrain using a Level of Detail (LOD) model. Advanced query functions, data accessing, data management and spatial analysis, which are executed in the traditional 2D GIS, are provided to users in a 3D environment by continuously transforming information between the 2D GIS subsystem and the 3D subsystem. The 3D data are organized and displayed by Keyhole Markup Language (KML) and textured 3D models in the COLLAborative Design Activity (COLLADA) format. The prototype demonstrates that this hybrid system has effectively addressed the three key issues identified above and that it can seamlessly integrate 2D GIS and 3D visualization. The hybrid system has great potential to be employed in many application domains, such as urban planning, landscape design and environmental decision making, among others, to enhance the 3D design capability and facilitate public participation in the planning, design and decision-making process. 相似文献
3.
Identifying a route that avoids obstacles in continuous space is important for infrastructure alignment, robotic travel, and virtual object path planning, among others, because movement through space is not restricted to a predefined road or other network. Vector and raster GIS (geographic information system) solution approaches have been developed to find good/efficient routes. On the vector side, recent solution approaches exploit spatial knowledge and utilize GIS functionality, offering significant computational advantages in finding an optimal solution to this path routing problem. Raster‐based shortest path techniques are widely applied in route planning for wayfinding, corridor alignment, robotics and video gaming to derive an obstacle avoiding path, but represent an approximation approach for solving this problem. This research compares vector and raster approaches for identifying obstacle‐avoiding shortest paths/routes. Empirical assessment is carried out for a number of planning applications, highlighting representational issues, computational requirements and resulting path efficiency. 相似文献
4.
Tijs Neutens Nico Van de Weghe Frank Witlox Philippe De Maeyer 《Journal of Geographical Systems》2008,10(1):89-107
Time-geographic concepts are effective tools for the geovisualization of human activity patterns and to assess individual
accessibility. In their traditional form, however, time-geographic concepts assume uniform travel velocities in an isotropic
and homogeneous space. Because transportation systems confine travellers to links of road and rail networks with time-varying
flows, these premises are typically unsatisfied in real-world situations. This paper provides an innovative approach to ameliorate
the realism and applicability of space–time prisms by developing new three-dimensional space–time objects. Three-dimensional
solid models which account for non-uniform movement are discussed, and their usefulness is assessed and illustrated by means
of an example.
相似文献
5.
A Space-Time GIS Approach to Exploring Large Individual-based Spatiotemporal Datasets 总被引：3，自引：0，他引：3
The increasing number of large individual-based spatiotemporal datasets in various research fields has challenged the GIS community to develop analysis tools that can efficiently help researchers explore the datasets in order to uncover useful information. Rooted in Hägerstrand's time geography, this study presents a generalized space-time path (GSTP) approach to facilitating visualization and exploration of spatiotemporal changes among individuals in a large dataset. The fundamental idea of this approach is to derive a small number of representative space-time paths (i.e. GSTPs) from the raw dataset by identifying spatial cluster centers of observed individuals at different time periods and connecting them according to their temporal sequence. A space-time GIS environment is developed to implement the GSTP concept. Different methods of handling temporal data aggregation and the creation of GSTPs are discussed in this article. Using a large individual-based migration history dataset, this study successfully develops an operational space-time GIS prototype in ESRI's ArcScene and ArcMap to provide a proof-of-concept study of this approach. This space-time GIS system demonstrates that the proposed GSTP approach can provide a useful exploratory analysis and geovisualization environment to help researchers effectively search for hidden patterns and trends in such datasets. 相似文献
6.
Network Density Estimation: A GIS Approach for Analysing Point Patterns in a Network Space 总被引：4，自引：0，他引：4
Giuseppe Borruso 《Transactions in GIS》2008,12(3):377-402
Human activities and more generally the phenomena related to human behaviour take place in a network‐constrained subset of the geographical space. These phenomena can be expressed as locations having their positions configured by a road network, as address points with street numbers. Although these events are considered as points on a network, point pattern analysis and the techniques implemented in a GIS environment generally consider events as taking place in a uniform space, with distance expressed as Euclidean and over a homogeneous and isotropic space. Network‐spatial analysis has developed as a research agenda where the attention is drawn towards point pattern analytical techniques applied to a space constrained by a road network. Little attention has been put on first order properties of a point pattern (i.e. density) in a network space, while mainly second order analysis such as nearest neighbour and K‐functions have been implemented for network configurations of the geographical space. In this article, a method for examining clusters of human‐related events on a network, called Network Density Estimation (NDE), is implemented using spatial statistical tools and GIS packages. The method is presented and compared to conventional first order spatial analytical techniques such as Kernel Density Estimation (KDE). Network Density Estimation is tested using the locations of a sample of central, urban activities associated with bank and insurance company branches in the central areas of two midsize European cities, Trieste (Italy) and Swindon (UK). 相似文献
7.
'Situating' Simulation to Model Human Spatio-Temporal Interactions: An Example Using Crime Events 总被引：3，自引：0，他引：3
Elizabeth R Groff 《Transactions in GIS》2007,11(4):507-530
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. 相似文献
8.
Geo‐SOM is a useful geovisualization technique for revealing patterns in spatial data, but is ineffective in supporting interactive exploration of patterns hidden in different Geo‐SOM sizes. Based on the divide and group principle in geovisualization, the article proposes a new methodology that combines Geo‐SOM and hierarchical clustering to tackle this problem. Geo‐SOM was used to “divide” the dataset into several homogeneous subsets; hierarchical clustering was then used to “group” neighboring homogeneous subsets for pattern exploration in different levels of granularity, thus permitting exploration of patterns at multiple scales. An artificial dataset was used for validating the method's effectiveness. As a case study, the rush hour motorcycle flow data in Taipei City, Taiwan were analyzed. Compared with the best result generated solely by Geo‐SOM, the proposed method performed better in capturing the homogeneous zones in the artificial dataset. For the case study, the proposed method discovered six clusters with unique data and spatial patterns at different levels of granularity, while the original Geo‐SOM only identified two. Among the four hierarchical clustering methods, Ward's clustering performed the best in pattern discovery. The results demonstrated the effectiveness of the approach in visually and interactively exploring data and spatial patterns in geospatial data. 相似文献
9.
Abstract Visualization techniques have been developed to recreate natural landscapes, but little has been done to investigate their potential for illustrating land cover change using spatio‐temporal data. In this work, remote sensing, geographic information systems (GIS) and visualization techniques were applied to generate realistic computer visualizations depicting the dynamic nature of forested environments. High resolution digital imagery and aerial photography were classified using object‐oriented methods. The resulting classifications, along with preexisting land cover datasets, were used to drive the correct placement of vegetation in the visualized landscape, providing an accurate representation of reality at various points in time. 3D Nature's Visual Nature Studio was used to construct a variety of realistic images and animations depicting forest cover change in two distinct ecological settings. Visualizations from Yellowstone National Park focused on the dramatic impact of the 1988 fire upon the lodgepole pine forest. For a study area in Kansas, visualization techniques were used to explore the continuous human‐land interactions impacting the eastern deciduous forest and tallgrass prairie ecotone between 1941 and 2002. The resulting products demonstrate the flexibility and effectiveness of visualizations for representing spatio‐temporal patterns such as changing forest cover. These geographic visualizations allow users to communicate findings and explore new hypotheses in a clear, concise and effective manner. 相似文献
10.
When studying spatial patterns, GIScientists often employ distance‐based methods and techniques, such as network analysis. When studying human behavior, however, spatial patterns often emerge that cannot be adequately examined assuming a physical conceptualization of distance. Such patterns emerged during our study of the process of ghettoization of Jews as implemented in Budapest during the course of 1944. As part of an NSF‐sponsored research project on the geography of the Holocaust, we built a Historical GIS of the Budapest Ghetto with the objective of discovering patterns of Jewish concentration and dispersion as well as simulating potential daily spatial interactions between the Jewish and the non‐Jewish population. Spatial analytical techniques allowed us to discover distinct spatial patterns of isolation, interrelation and concentration, but a whole set of patterns appeared that were the opposite of what we expected, and that could only be explained by thinking of distance not in spatial terms but in social ones. In this article we employ social network analysis to examine the geography of oppression in the Budapest ghetto. What jumped out from our study is the interweaving of space and place – intended as a community bounded by social relations and living in a specific time and location. 相似文献
11.
Waldo Tobler frequently reminded us that the law named after him was nothing more than calling for exceptions. This article discusses one of these exceptions. Spatial relations between points are frequently modeled as vectors in which both distance and direction are of equal prominence. However, in Tobler's first law of geography, such a relation is described only from the perspective of distance by relating the decreasing similarity of observations in some attribute space to their increasing distance in geographic space. Although anisotropic versions of many geographic analysis techniques, such as directional semivariograms, anisotropy clustering, and anisotropic point pattern analysis, have been developed over the years, direction remains on the level of an afterthought. We argue that, compared to distance, directional information is still under‐explored and anisotropic techniques are substantially less frequently applied in everyday GIS analysis. Commonly, when classical spatial autocorrelation indicators, such as Moran's I, are used to understand a spatial pattern, the weight matrix is only built from distance, without direction being considered. Similarly, GIS operations, such as buffering, do not take direction into account either, with distance in all directions being treated equally. In reality, meanwhile, particularly in urban structures and when processes are driven by the underlying physical geography, direction plays an essential role. In this article we ask whether the development of early GIS, data (sample) sparsity, and Tobler's law lead to a theory‐induced blindness for the role of direction. If so, is it possible to envision direction becoming a first‐class citizen of equal importance to distance instead of being an afterthought only considered when the deviation from a perfect circle becomes too obvious to be ignored? 相似文献
12.
Antonio Rodriguez Cervilla Siham Tabik Jesús Vías Matías Mérida Luis F. Romero 《Transactions in GIS》2017,21(3):591-607
The 3D perception of the human eye is more impressive in irregular land surfaces than in flat land surfaces. The quantification of this perception would be very useful in many applications. This article presents the first approach to determining the visible volume, which we call the 3D‐viewshed, in each and all the points of a DEM (Digital Elevation Model). Most previous visibility algorithms in GIS (Geographic Information Systems) are based on the concept of a 2D‐viewshed, which determines the number of points that can be seen from an observer in a DEM. Extending such a 2D‐viewshed to 3D space, then to all the DEM‐points, is too expensive computationally since the viewshed computation per se is costly. In this work, we propose the first approach to compute a new visibility metric that quantifies the visible volume from every point of a DEM. In particular, we developed an efficient algorithm with a high data and calculation re‐utilization. This article presents the first total‐3D‐viewshed maps together with validation results and comparative analysis. Using our highly scalable parallel algorithm to compute the total‐3D‐viewshed of a DEM with 4 million points on a Xeon Processor E5‐2698 takes only 1.3 minutes. 相似文献
13.
An Integrated GIS Approach to Accessibility Analysis 总被引：5，自引：0，他引：5
Accessibility is an important element in evaluating existing land‐use patterns and transportation services, predicting travel demands and programming transportation investments in urban transportation planning. This paper presents an integrated GIS approach to accessibility analysis, which provides a general framework for integrated use of GIS, travel impedance measurement tools and accessibility measures to support the accessibility analysis process, including formulating the concept of accessibility, selecting or developing accessibility measures, specifying the accessibility measures, deriving the accessibility values using the selected or developed accessibility measures, and presenting and interpreting the accessibility values. An integrated GIS tool, ACCESS, designed for implementing the integrated approach is also described and illustrated. 相似文献
14.
Shinji Masumoto Venkatesh Raghavan Go Yonezawa Tatsuya Nemoto Kiyoji Shiono 《Transactions in GIS》2004,8(2):211-223
The present work aims at introducing a basic theory, implementing methodology and algorithms for 3‐D modeling, and visualizing a geologic model using the Open Source Free GIS GRASS environment. A 3‐D geologic model is constructed from the boundary surfaces of geologic units and the logical model of geologic structure. The algorithms for construction and visualization of the proposed model are based on the geologic function g . The geologic function g assigns a unique geologic unit to every point in the objective 3‐D space. The boundary surface that divides the objective space into two subspaces is estimated using data from field survey. The logical model showing the hierarchical relationship between these boundary surfaces and geologic units can be automatically generated based on the stratigraphic sequence and knowledge of geologic structures. Based on these algorithms, a 3‐D geologic model can be constructed virtually in the GRASS GIS. Applying this model, various geologic surfaces and section models can be visualized in the GRASS GIS environment. “Nviz” was used for dynamic visualization of geologic cross‐sections and generation of animated image sequences. Further, the described algorithms and methods are applied and an online 3‐D geologic modeling system is developed. 相似文献
15.
16.
随着空间信息技术和网络技术的发展,地理信息系统（GIS）也在不断地从2维世界走向3维世界,从GIS应用走向GIS服务。在此基础上,本文提出了3DGIS Web服务,并设计了基于SOA的3DGIS Web服务多层体系结构、3DGIS Web服务的数据源和API框架,论述了3DGIS Web服务和现有的2维GIS Web服务集成需要解决的关键技术问题。 相似文献
17.
一种三维GIS混合数据结构研究 总被引：122，自引：8，他引：122
本文在对三维ＧＩＳ中多种数据结构进行分析的基础上，发展了三维行程码方法，完善了有关四面体格网的理论和算法，提出了一种基于八叉树和四面体格网的混合数据结构，以及基于混合数据结构的３Ｄ ＧＩＳ概念，最后通过实验对有关理论成果进行了验证。 相似文献
18.
19.
近年来,快速发展的高速铁路、城际轨道等高速交通方式对旅游的影响日益显现。本文以珠三角地区运营和规划城际轨道为例,基于GIS网络分析技术和通达性指标,探讨了城际轨道通车前后对珠三角地区旅游空间格局的影响。结果表明:城轨开通将会产生显著的"时空压缩"效应,旅游景点总通达时间降幅达32.87%,旅游景点平均通达时间减少0.7 h;不同区域通达性水平提升具有差异性,城际轨道站点及其周边地区成为通达性水平提升最大的地区,随着与站点距离逐渐增加,通达性变化程度逐渐降低;城轨开通后各地区通达性水平差异逐渐缩小,并趋于均衡;城轨影响下的旅游景点通达性的影响具有"廊道效应"与"隧道效应"相结合的特征,空间格局由开通前的"中心-外围"态势向面状均衡分布格局转变。城际轨道带来的"时空压缩"效应,在扩大了旅游景点市场范围的同时,由于通行时间成本降低,进一步提高了旅游出行的效率。 相似文献
20.
《制图学和地理信息科学》2013,40(1):20-35
Soil maps are an important and integral component of national geospatial data infrastructures. The creation of these maps involves a geovisualization exercise whereby soil scientists develop cognitive models that correlate observable landscape features to soil occurrence. This is traditionally an analog process, cognitively demanding, time consuming, and invariably non-collaborative. A new geovirtual soil mapping technique is proposed in this paper in the form of an innovative Experiential GIS (EGIS) environment. This immersive environment enables soil maps to be constructed through experiencing and interacting with spatial data through immersion in 3D geovirtual scenes. The system outlined integrates GIS, immersive geovisualization, and robust geodatabase capabilities. Four soil scientists with extensive soil mapping experience ranging from 5 to over 20 years are concurrently immersed in the same 3D geovirtual landscape which more closely mirrors the way in which we view the world around us. The soil scientists are immersed within the 3D scene where they are essentially freed from the laws of physics, and may roam anywhere across the landscape as if in a virtual helicopter. The landscape is draped with any combination of orthoimagery and GIS-derived data allowing soil scientists to interpret, digitally delineate, and attribute soil boundaries. Exploiting the EGIS technology while maintaining the centrality of the soil scientist in soil interpretation and soil map production, promises considerable resource efficiencies than those achieved in traditional soil survey. The paper lays out the nature of this potential paradigm shift in soil mapping. The results of using this technology to construct soil geographic knowledge are also discussed in terms of soil map detail, cost efficiencies, time effectiveness, system usability, geocollaborative soil mapping advantages, and the reduced cognitive workload on practicing soil scientists. 相似文献