共查询到20条相似文献，搜索用时 312 毫秒
1.
Debasis Ghosh 《Transactions in GIS》2008,12(3):365-375
Spatial decision making is characterized by problems associated with multiple and conflicting alternatives relating to geographical features and their attributes. As such, the search for the best possible alternative from a large set of such alternatives can be a daunting task. The aim of integrating GIS with Multi‐Criteria Decision Making (MCDM) is to develop a well‐defined process that can scan through such extensive fields of choice to arrive at the best possible solution. Goal Programming is one tool (developed in conjunction with MCDM) that can handle a problem with multiple, conflicting and incommensurable alternatives, and this article explains how the loose coupling technique can integrate MCDM with GIS to assist decision making among competing alternatives. As an example, this methodology has been applied for community development purposes in the Hooghly District of West Bengal, India. 相似文献
2.
Network routing problems generally involve multiple objectives which may conflict one another. An effective way to solve such problems is to generate a set of Pareto-optimal solutions that is small enough to be handled by a decision maker and large enough to give an overview of all possible trade-offs among the conflicting objectives. To accomplish this, the present paper proposes an adaptive method based on compromise programming to assist decision makers in identifying Pareto-optimal paths, particularly for non-convex problems. This method can provide an unbiased approximation of the Pareto-optimal alternatives by adaptively changing the origin and direction of search in the objective space via the dynamic updating of the largest unexplored region till an appropriately structured Pareto front is captured. To demonstrate the efficacy of the proposed methodology, a case study is carried out for the transportation of dangerous goods in the road network of Hong Kong with the support of geographic information system. The experimental results confirm the effectiveness of the approach. 相似文献
3.
以地理空间情报服务于反恐为需求牵引,采用全球恐怖主义数据库(GTD)为数据源,将时空叙事结构作为分析模型,以时间要素和空间要素作为线索,进行地理空间叙事,对事件和对象的多维属性进行可视化,借助多视图人机交互式分析方法和交互技术,构建了基于JavaScript的地理空间情报可视分析平台,并根据分析任务进行了案例分析,为基于活动的地理空间情报研究探索一条新的思路。 相似文献
4.
《测量评论》2013,45(73):131-137
AbstractMany have tried their hands at one time or another at developing practical methods in respect to the solutions of the four fundamental problems viz., (1) space resection, (2) orientation of photograph in space and relative to one another, (3) space intersection, and (4) photogrammetric extension of surveys without ground control. The trouble so far has been that each worker had his own particular problem to solve and hence a completely general and comprehensive approach to the problems is lacking. In this paper these four fundamental problems are considered as essentially one of a system of linear transformations, from one set of coordinates to another, bearing in mind the existence of the significant correspondence between pairs of image points and points in space. 相似文献
5.
利用GIS和模糊层次分析法的南极考察站选址研究 总被引：1，自引：0，他引：1
南极考察站选址问题关系南极考察站的安全、功能和运行效率。从科考兴趣、环境条件、后勤保障和地形条件四个方面构建南极考察站选址指标体系,将GIS和模糊层次分析法集成构建一种新的数学模型,用于确定南极考察站建立的适宜性区域,实现选址评价。在对已建南极考察站选址分析的基础上进行了模型验证,得到模型的准确度为98.89%,证明此模型具有较高的准确性和较好的适用性。 相似文献
6.
The p‐median problem (PMP) is one of the most applied location problems in urban and regional planning. As an NP‐hard problem, the PMP remains challenging to solve optimally, especially for large‐sized problems. A number of heuristics have been developed to obtain PMP solutions in a fast manner. Among the heuristics, the Teitz and Bart (TB) algorithm has been found effective for finding high‐quality solutions. In this article, we present a spatial‐knowledge‐enhanced Teitz and Bart (STB) heuristic method for solving PMPs. The STB heuristic prioritizes candidate facility sites to be examined in the solution set based on the spatial distribution of demand and service provision. Tests based on a range of PMPs demonstrate the effectiveness of the STB heuristic. This new algorithm can be incorporated into current commercial GIS packages to solve a wide range of location‐allocation problems. 相似文献
7.
传统的后方交会最小二乘解法需要良好的外方位元素初值。在无初值或者初值不够精确的情况下,最小二乘迭代不容易收敛。在近景摄影测量或者计算机视觉等领域,往往不提供良好的初值,无法适用传统的后方交会解法。针对上述情况,本文提出了一种基于单应性矩阵的后方交会直接解法,在不需要初值的情况下,获取外方位元素的直接解。该方法根据单应性矩阵所描述的平面几何关系,利用单应性矩阵内在的约束条件,将后方交会问题转换为一个二元二次方程组的求解问题。该方法受舍入误差影响小,在无偶然误差的情况下,解算精度能达到10–9量级,能够避免传统直接解法计算复杂的问题,为传统的平差迭代解法提供良好的初值。此外,在多个控制点共面的情况下,该方法能够直接获得外方位元素的精确解。实验结果表明:在各种不同倾角拍摄的情况下,该方法均能够获得稳定的外方位元素,为后续的后方交会最小二乘算法提供良好的初值。采用本文方法计算的初值参与平差,能够达到与人工给定初值平差一致的精度,且迭代收敛速度是人工给定初值平差的2倍以上。在控制点共面的情况下,该方法的反投影精度能够达到亚像素级,且精度优于大部分主流的直接解法。 相似文献
8.
The multi‐objective land allocation problem is to optimize the selection of land for different uses based on a set of decision objectives. For most applications, a geographical information system (GIS) is either absent or loosely coupled through file exchange. In this article the evolutionary algorithm (EA), a heuristic solution method for optimization problems, is integrated with a raster GIS to form a spatial decision support system (SDSS) for multi‐objective conservation reserve design. The SDSS effectively combines the functions of a GIS for data management, analysis, and visualization, with the optimization capability of the EA; and provides a uniform way to solve conservation reserve design problems with different types of constraints and objectives. The SDSS is demonstrated through application to the creation of conservation reserves in Bolivia to protect 17 endemic mammals. 相似文献
9.
Grid-enabling Geographically Weighted Regression: A Case Study of Participation in Higher Education in England 总被引：2，自引：0，他引：2
Richard Harris Alex Singleton Daniel Grose Chris Brunsdon Paul Longley 《Transactions in GIS》2010,14(1):43-61
Geographically Weighted Regression (GWR) is a method of spatial statistical analysis used to explore geographical differences in the effect of one or more predictor variables upon a response variable. However, as a form of local analysis, it does not scale well to (especially) large data sets because of the repeated processes of fitting and then comparing multiple regression surfaces. A solution is to make use of developing grid infrastructures, such as that provided by the National Grid Service (NGS) in the UK, treating GWR as an "embarrassing parallel" problem and building on existing software platforms to provide a bridge between an open source implementation of GWR (in R) and the grid system. To demonstrate the approach, we apply it to a case study of participation in Higher Education, using GWR to detect spatial variation in social, cultural and demographic indicators of participation. 相似文献
10.
Yukio Sadahiro 《Journal of Geographical Systems》2011,13(4):373-391
A spatial tessellation is a set of regions that are collectively exhaustive and mutually exclusive except for the boundaries.
In geographical analysis, it may represent such administrative units as census tracts, postal zones, and electoral or school
districts. Spatial tessellations of a certain area are often closely related to each other. Areas of local communities are
related to school districts, market areas of retail stores, and administrative units. Postal zones and census tracts are determined
by collecting or dividing administrative units. Analysis of such relations among tessellations often reveals their underlying
spatial phenomena. To this end, this paper proposes a new exploratory method for analyzing the relations among spatial tessellations.
It aims to detect spatial patterns, especially those with a hierarchical structure, and to provide a tessellation classification
scheme. Topological relations and similarity measures are introduced to evaluate the relations between tessellation pair.
For more tessellations, tree representations are proposed. These not only visualize relations, but also provide a means of
classifying tessellations. The method is applied to the analysis of two sets of spatial tessellations: one with five hypothetical
tessellations, and another with 34 candidate plans for the new Doshusei administrative system in Japan. The application reveals
the properties of the method and quantitative measures used in analysis. 相似文献
11.
12.
Geovisualization of Human Hybrid Activity-Travel Patterns 总被引：4，自引：0，他引：4
While GIS‐based geovisualization techniques have been fruitfully employed in a wide range of fields, they have not been applied to explore human hybrid activity‐travel patterns (i.e. the patterns of people's activities and/or travel in both the physical and virtual worlds). This study develops two geovisualization approaches using 3D and 2D GIS techniques to address the difficulties faced by past studies. First, the notions of information cube and hybrid 3D space‐time paths are developed to accommodate cyberspatial activities in exploratory data analysis. Second, a new representation of 2D space‐time paths that incorporates parallel coordinate plots is developed for exploring the multiple attributes of people's Internet and physical activities. These two methods were implemented using ArcObjects and the Visual Basic for Applications environment in ArcGIS. They were used to visualize a complex Internet‐activity diary dataset collected in Columbus (Ohio, USA). The study shows that the 3D and 2D geovisualization methods developed allow us to uncover important patterns in hybrid human activity‐travel behavior. 相似文献
13.
Urban sprawl has led to environmental problems and large losses of arable land in China. In this study, we monitor and model urban sprawl by means of a combination of remote sensing, geographical information system and spatial statistics. We use time-series data to explore the potential socio-economic driving forces behind urban sprawl, and spatial models in different scenarios to explore the spatio-temporal interactions. The methodology is applied to the city of Wuhan, China, for the period from 1990 to 2013. The results reveal that the built-up land has expanded and has dispersed in urban clusters. Population growth, and economic and transportation development are still the main causes of urban sprawl; however, when they have developed to certain levels, the area affected by construction in urban areas (Jian Cheng Qu (JCQ)) and the area of cultivated land (ACL) tend to be stable. Spatial regression models are shown to be superior to the traditional models. The interaction among districts with the same administrative status is stronger than if one of those neighbors is in the city center and the other in the suburban area. The expansion of urban built-up land is driven by the socio-economic development at the same period, and greatly influenced by its spatio-temporal neighbors. We conclude that the integration of remote sensing, a geographical information system, and spatial statistics offers an excellent opportunity to explore the spatio-temporal variation and interactions among the districts in the sprawling metropolitan areas. Relevant regulations to control the urban sprawl process are suggested accordingly. 相似文献
14.
Stefan Hahmann Jakob Miksch Bernd Resch Johannes Lauer Alexander Zipf 《地球空间信息科学学报》2018,21(3):247-256
AbstractFinding the shortest path through open spaces is a well-known challenge for pedestrian routing engines. A common solution is routing on the open space boundary, which causes in most cases an unnecessarily long route. A possible alternative is to create a subgraph within the open space. This paper assesses this approach and investigates its implications for routing engines. A number of algorithms (Grid, Spider-Grid, Visibility, Delaunay, Voronoi, Skeleton) have been evaluated by four different criteria: (i) Number of additional created graph edges, (ii) additional graph creation time, (iii) route computation time, (iv) routing quality. We show that each algorithm has advantages and disadvantages depending on the use case. We identify the algorithms Visibility with a reduced number of edges in the subgraph and Spider-Grid with a large grid size to be a good compromise in many scenarios. 相似文献
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16.
Guannan Li Shengsheng Lin Xiu Lu Liangchen Zhou Bingxian Lin Guonian Lv 《Transactions in GIS》2023,27(2):425-449
Identifying and tracking objects in surveillance videos is an important means of mining information during surveillance. Currently, most object-tracking methods rely only on image features, which cannot accurately express the motion of the tracked object in real geographical scenes and are easily influenced by occlusion and surrounding objects having similar features. However, tracked objects, such as pedestrians and vehicles, usually move in geographical space with fixed patterns of motion, and the motion in a short time is constrained by geographical space and time, the motion trajectory is predictable, and the range of motion is limited. Therefore, based on the SiamFC object tracking framework, this study introduces geographical spatiotemporal constraints into the tracking framework and proposes the GeoSiamFC method. The objective of this is to: (1) construct the mapping relationship between geographical space and image space to solve the problem that the pixel movement within the image after perspective imaging cannot accurately express the motion of the tracked object in a real geographical scene; (2) add candidate search areas according to the predicted trajectory location to correct the tracking errors caused by the occlusion of the object; and (3) focus on the search for the range of motion of the mapped pixel within the image space according to the limited geographical range of motion of the tracked objects in a certain time to reduce the interference of similar objects within the search area. In this study, separate experiments were conducted on a common test dataset using multiple methods to deal with challenges such as occlusion and illumination changes. In addition, a robust test dataset with noise addition and luminance adjustment based on the common test dataset was used. The results show that GeoSiamFC outperforms other object-tracking methods in the common test dataset with a precision score of 0.995 and a success score of 0.756 compared with most other object-tracking algorithms under the base condition of using only shallow networks. Moreover, GeoSiamFC maintained the highest precision score (0.970) and high success score (0.734) in the more challenging robust test dataset as well. The tracking speed of 59 frames per second far exceeds the real-time requirement of 25 FPS. Geographical spatiotemporal constraints were considered to improve tracker performance while providing real-time feedback on the motion trajectory of the target in geographical space. Thus, the proposed method is suitable for real-time tracking of the motion trajectory of a target in real geographical scenes in various surveillance videos. 相似文献
17.
Relative orientation is one of the fundamental steps in forming a photogrammetric model. Whilst relative orientation is straightforward in most cases of aerial photogrammetry this may not be the case in close range photogrammetry where the nature of the photographs and the cameras being used often raise unfamiliar problems. This paper addresses the problem of performing relative orientation of non-metric photographs under unstable conditions where there are no ground control points and the ray intersection geometry is poor. The relative orientation problem is approached from several viewpoints, including a method that relies on little information about the exterior or relative orientation parameters. The solution is based on an iterative process, in which a set of three virtual control points (VCPs) is created, using photo coordinates and range ratios. The validity of the VCPs is checked during every iteration by an estimation of the coplanarity condition using two or more conjugate checkpoints. During the iteration a database is formed, which is then used to obtain a net of VCPs that fulfil the coplanarity condition for the checkpoints. The VCPs are then used to compute the "relative" exterior orientation by space resection. The proposed method was tested on both simulated and real photographs and was found to have some advantages over more commonly used techniques. 相似文献
18.
The evidence from collaborative GIS problem solving indicates that although environmental problems are context dependent, meaningful solutions are framed around the core issues of multiple stakeholder interests, complexity, wicked problems, ill‐defined problem specification, and their spatial characteristics. Based on subsets of these issues, there exists a number of overlapping collaborative GIS designs and processes. The goal of this study is to reconcile the overlap by modeling a core collaborative GIS design and process. General systems theory is used to classify core technical components of the collaborative GIS design, and soft systems theory characterizes the human activity dynamics of the collaborative process. Further, object oriented principles are used to generate a flexible problem domain design, and the unified modeling language (UML) visually describes the structure and behavior of the collaborative process. The core formalism facilitates GIS process integration, standardization, reusability, ontology design, and rapid solution design in new problem contexts. The collaborative spatial Delphi (CSD) methodology is a proof of concept. This research contributes to the design and specification of a core collaborative GIS model, a reusable pattern, and their ontological impacts. 相似文献
19.
E. W. Grafarend 《Journal of Geodesy》2001,75(7-8):363-390
In a comparison of the solution of the spherical horizontal and vertical boundary value problems of physical geodesy it is
aimed to construct downward continuation operators for vertical deflections (surface gradient of the incremental gravitational
potential) and for gravity disturbances (vertical derivative of the incremental gravitational potential) from points on the
Earth's topographic surface or of the three-dimensional (3-D) Euclidean space nearby down to the international reference sphere
(IRS). First the horizontal and vertical components of the gravity vector, namely spherical vertical deflections and spherical
gravity disturbances, are set up. Second, the horizontal and vertical boundary value problem in spherical gravity and geometry
space is considered. The incremental gravity vector is represented in terms of vector spherical harmonics. The solution of
horizontal spherical boundary problem in terms of the horizontal vector-valued Green function converts vertical deflections
given on the IRS to the incremental gravitational potential external in the 3-D Euclidean space. The horizontal Green functions
specialized to evaluation and source points on the IRS coincide with the Stokes kernel for vertical deflections. Third, the
vertical spherical boundary value problem is solved in terms of the vertical scalar-valued Green function. Fourth, the operators
for upward continuation of vertical deflections given on the IRS to vertical deflections in its external 3-D Euclidean space
are constructed. Fifth, the operators for upward continuation of incremental gravity given on the IRS to incremental gravity
to the external 3-D Euclidean space are generated. Finally, Meissl-type diagrams for upward continuation and regularized downward
continuation of horizontal and vertical gravity data, namely vertical deflection and incremental gravity, are produced.
Received: 10 May 2000 / Accepted: 26 February 2001 相似文献
20.