共查询到10条相似文献，搜索用时 187 毫秒
1.
Yibin Ren Yang Zhang 《International journal of geographical information science》2019,33(9):1894-1912
Recently, researchers have introduced deep learning methods such as convolutional neural networks (CNN) to model spatio-temporal data and achieved better results than those with conventional methods. However, these CNN-based models employ a grid map to represent spatial data, which is unsuitable for road-network-based data. To address this problem, we propose a deep spatio-temporal residual neural network for road-network-based data modeling (DSTR-RNet). The proposed model constructs locally-connected neural network layers (LCNR) to model road network topology and integrates residual learning to model the spatio-temporal dependency. We test the DSTR-RNet by predicting the traffic flow of Didi cab service, in an 8-km2 region with 2,616 road segments in Chengdu, China. The results demonstrate that the DSTR-RNet maintains the spatial precision and topology of the road network as well as improves the prediction accuracy. We discuss the prediction errors and compare the prediction results to those of grid-based CNN models. We also explore the sensitivity of the model to its parameters; this will aid the application of this model to network-based data modeling. 相似文献
2.
M. Mainguenaud 《International journal of geographical information science》2013,27(6):575-593
Abstract This paper presents a data model to manage networks with a Geographical Information System with some consideration of the path operator. The data model is based on the merge of graph theory concepts and the object-oriented paradigm. The introduction of the Master_nodes (with respect to Master_edges) allows definition of a node (with respect to an edge) as an abstraction of a sub-network. A network can be defined using several levels of definition (detail) following the importance of the nodes (with respect to the edges) within an application. The object-oriented concepts are applied to both the alphanumerical data part and to the modelling part of the topology of the graph. The data manipulation operators are basic operators. These operators are the union, an intersection and a difference. More elaborated operators, such as under constraints paths, are obtained by combining these basic operators. We present some considerations of the path operator in a GIS context and introduce the concept of the ‘Open Graph Assumption’ and the notion of direction. These notions take full advantage of the data model and represent an alternative way of defining the path operator. This modelling is well adapted to take account of multi-level networks (i.e., the definition of a view in the context of a multi-user configuration or cartographic generalization). 相似文献
3.
Qiliang Liu Zhihui Wu Wenkai Liu Yaolin Liu 《International journal of geographical information science》2020,34(10):1903-1929
ABSTRACT Urban black holes and volcanoes are typical traffic anomalies that are useful for optimizing urban planning and maintaining public safety. It is still challenging to detect arbitrarily shaped urban black holes and volcanoes considering the network constraints with less prior knowledge. This study models urban black holes and volcanoes as bivariate spatial clusters and develops a network-constrained bivariate clustering method for detecting statistically significant urban black holes and volcanoes with irregular shapes. First, an edge-expansion strategy is proposed to construct the network-constrained neighborhoods without the time-consuming calculation of the network distance between each pair of objects. Then, a network-constrained spatial scan statistic is constructed to detect urban black holes and volcanoes, and a multidirectional optimization method is developed to identify arbitrarily shaped urban black holes and volcanoes. Finally, the statistical significance of multiscale urban black holes and volcanoes is evaluated using Monte Carlo simulation. The proposed method is compared with three state-of-the-art methods using both simulated data and Beijing taxicab spatial trajectory data. The comparison shows that the proposed method can detect urban black holes and volcanoes more accurately and completely and is useful for detecting spatiotemporal variations of traffic anomalies. 相似文献
4.
基于路网相关性的分布式增量交通流大数据预测方法 总被引：2，自引：1，他引：1
针对城市道路拥堵问题的日益加剧的问题,智能化城市交通管理平台是缓解拥堵问题的有效方法,利用交通流大数据预测结果进行交通诱导,能够指导用户调整出行方案,有效缓解交通压力。研究了交通流大数据的分布式增量聚合方法,对海量交通流数据进行清洗统计,为交通流预测提供数据基础,基于交通流在路网中上下游路段的相关性分析,利用路口转弯率多阶分配将该相关性量化,构建基于路网相关性的空间权重矩阵,完成对于STARIMA模型的改进。通过应用试验证明,该方法能更准确的进行交通流预测,为交通诱导信息发布提供依据。 相似文献
5.
Recently, the Chinese government raised an urban planning policy which suggests communities open their private roads for public transport and establish street networks with high spatial density in cities. In this context, the purpose of this study is to analyze the potential changes to street network accessibility using GIS techniques and to provide spatial information that may influence the decision making of urban managers. In addition to the existing street network data in the case study city, Shenzhen, intra-community roads are extracted from building footprints in GIS topographic database and used to construct a potential street network with respect to the community opening policy. An automatic GIS-based method is proposed here to analyze the location advantage information in the simulated urban environment, by combining Delaunay triangulation model and graph theory concepts. Specifically, we establish a two-step framework based on the spatial relationships between roads and buildings. Firstly, intra-community roads between neighboring building footprints are generated using a Delaunay triangulation skeleton model, and with the existing inter-community roads they form the simulated network. Secondly, street centrality indices of the current and simulated networks are compared in terms of closeness, betweenness and straightness. Results indicate that after applying the policy the global accessibility in the city would be increased at some places and decreased at others, and places' directness among others would be generally improved. In addition, the skeleton of central routes for through traffic would not change much. The presented method can also be applied to other cities. 相似文献
6.
Gang Liu Yongshu Li Jun Yang Guolin Cai Xiping Zhang 《International journal of geographical information science》2014,28(1):39-55
Traffic flow transmission is a constantly important aspect of complex networks, geographical information science, and other science and engineering fields. Previous studies have shown that vehicle flow is more strongly correlated with morphological properties of streets than those of axial lines. In addition, street-based topological representations are more suitable for vehicle flow prediction, as well as more memory-oriented and global in nature. In this study, we construct a dual graph to represent the street–street relationship and propose a routing strategy for networks on the basis of gravitational field theory. We aim to diminish traffic congestion and enhance the transmission performance of networks. We borrow from gravitational field theory in establishing a gravitational field stimulated by a node in packet transmission and in defining the corresponding gravitational field equation. On the basis of this study, we present a mathematical model and a routing strategy. Experimental results indicate that compared with the shortest path routing strategy, the proposed method considerably enhances network capacity and effectively balances network traffic flow, especially for congested networks. We achieve critical gravitation that can always maximize network capacity, regardless of the values of other parameters. 相似文献
7.
Integrating heterogeneous spatial data is a crucial problem for geographical information systems (GIS) applications. Previous studies mainly focus on the matching of heterogeneous road networks or heterogeneous polygonal data sets. Few literatures attempt to approach the problem of integrating the point of interest (POI) from volunteered geographic information (VGI) and professional road networks from official mapping agencies. Hence, the article proposes an approach for integrating VGI POIs and professional road networks. The proposed method first generates a POI connectivity graph by mining the linear cluster patterns from POIs. Secondly, the matching nodes between the POI connectivity graph and the associated road network are fulfilled by probabilistic relaxation and refined by a vector median filtering (VMF). Finally, POIs are aligned to the road network by an affine transformation according to the matching nodes. Experiments demonstrate that the proposed method integrates both the POIs from VGI and the POIs from official mapping agencies with the associated road networks effectively and validly, providing a promising solution for enriching professional road networks by integrating VGI POIs. 相似文献
8.
Taylor Anderson Suzana Dragićević 《International journal of geographical information science》2020,34(9):1792-1821
ABSTRACT Agent-based models (ABM) are used to represent a variety of complex systems by simulating the local interactions between system components from which observable spatial patterns at the system-level emerge. Thus, the degree to which these interactions are represented correctly must be evaluated. Networks can be used to discretely represent and quantify interactions between system components and the emergent system structure. Therefore, the main objective of this study is to develop and implement a novel validation approach called the NEtworks for ABM Testing (NEAT) that integrates geographic information science, ABM approaches, and spatial network representations to simulate complex systems as measurable and dynamic spatial networks. The simulated spatial network structures are measured using graph theory and compared with empirical regularities of observed real networks. The approach is implemented to validate a theoretical ABM representing the spread of influenza in the City of Vancouver, Canada. Results demonstrate that the NEAT approach can validate whether the internal model processes are represented realistically, thus better enabling the use of ABMs in decision-making processes. 相似文献
9.
基于高速公路流的江苏省城市网络空间结构与演化特征 总被引：4，自引：2，他引：4
高速交通网络是城市网络发育的重要指示器。以江苏省2004~2012年的高速公路流数据为支撑,辅以路网为背景,借助社区发现模型对其城市网络的空间结构与演化过程进行分析。结论如下：① 城市网络的演化由稀疏到稠密,但“南密北疏”的宏观格局与松散化的空间结构未发生明显改变;② 不同年份城市网络的空间结构可视为由多个“城市社区”组成,并凸显一体化效应、行政区效应、袭夺与被袭夺效应等区域效应;③ 苏南、苏中和苏北的空间关联特征可分别概括为“一体化、多层次”“由均一到分化”和“破碎化、分散化”的网络结构。在此基础上,归纳了一个涵盖城镇化中早期、中期和中后期的“破碎化、分散化网络-逐步分化的多层级网络-多中心、多层级网络”三阶段的城市网络演化模型。 相似文献
10.
Demin Xiong Duane F. Marble 《International journal of geographical information science》2013,27(6):769-789
Abstract The current research focuses upon the development of a methodology for undertaking real-time spatial analysis in a supercomputing environment, specifically using massively parallel SIMD computers. Several approaches that can be used to explore the parallelization characteristics of spatial problems are introduced. Within the focus of a methodology directed toward spatial data parallelism, strategies based on both location-based data decomposition and object-based data decomposition are proposed and a programming logic for spatial operations at local, neighborhood and global levels is also recommended. An empirical study of real-time traffic flow analysis shows the utility of the suggested approach for a complex, spatial analysis situation. The empirical example demonstrates that the proposed methodology, especially when combined with appropriate programming strategies, is preferable in situations where critical, real-time, spatial analysis computations are required. The implementation of this example in a parallel environment also points out some interesting theoretical questions with respect to the theoretical basis underlying the analysis of large networks. 相似文献