2008 Vol. 33, No. 4
Spatial information technology is one of three domain high techniques in the world.It is widely applying in the fields of urban planning,surveying,military,and other fields.Techniques from GIS,GPS and RS are booming in transportation studies and attracting a lot of researchers from universities,companies,and research institutes.This paper introduces the theories and methodologies for integrating spatial information technology for transportation studies.Then a lot of typical applications such as logistics management,intelligent navigation,traffic information services,and traffic securities are presented.The outlook of the integration of spatial information technology and transportation are highlighted at the end of this paper.
A storage and management method for GPS tracking data based on road features is proposed,considering that the car trajectories are road network constrained.The storage space is significantly reduced when only the information of road feature points is recoded and the 2-D geographic coordinates are transformed to linear referencing tags.With the advantage of less data redundancy,the road network associated tracking data can better support the further analysis and traffic information abstraction.
A multimodal composite transportation network model is developed in response to the multimodal travel requirement of travelers.A geometrical snapping model is presented for building the topology of multimodal composite network and the relative topology build algorithm is put forward based on this model.The model unites sub networks of different modes into a integrate graph structure,which provides the efficient data structure for multimodal route analyze.Experiment results demonstrate that the data model and algorithm are viable.
It is useful for sailing to monitor and control remotely the navigational marks which are located at both sides of the inland waterway.The monitoring system integrates the technologies of wireless communication,geo-sensor network,GPS,spatial information handling and others to collect and convey the real-time information about buoys,and to give alarms for abnormal situation of navigational marks.The electronic waterway map is the geographical foundation for representation of navigational marks' situation.It supports the retrieval,analysis,and representation of spatial information.The paper discusses the technologies of the dynamic electronic map used in the system,which includes map representation driven by event,map representation for the changing temporal-spatial features,visualization of multi-scale waterway data,extension of S57/S52 standard for inland waterway application,real-time monitoring and alarm for navigational marks.
Spatial arrangement is a key factor for layout optimization of fire protection facilities.The path analysis based on the proposed space-time allocation model provides a solid measure for the layout optimization. It is often simplified by using a circular area based on the facility location to represent a buffer zone or simply consider only the road segments that a fire engine has to travel.In this research,we introduce a hybrid measurement considering both travel time on the main roads and the inner part of a neighborhood for layout optimization of fire protection facilities.Furthermore,some indices are introduced to measure the service level of spatial arrangement of fire protection facilities quantitatively.Finally,some testing results are produced and presented by using modeling techniques in ArcGIS software and they show that the proposed approach is much more appropriate than the two simplified versions.
Bus transit transfer is a key problem in both transit assignment and transit trip planning.Conventionally the transfer is estimated with average waiting time,which prevents precise acquisition of the optimal route of a particular trip.Based on spatial data,transit features can be represented at different levels of detail.The data model at the detailed directional level provides possibility for precisely evaluating transfer impedance.
The paper proposes a method for the adaptive multiscale representation of navigation map for LBS applications.The method is able to automatically set a feasible scale according to geographical scope and the complexity of road network.Moreover,the method achieves multiple-scale representations of road network in a display screen.Initial experimental studies are shown in this paper.Further research will focus on the adaptive representations and visualizations of road network data.
Similarity is a psychological cognition,this paper defines the different distance and puts forward the similarity measuring model for linear spatial data(SMM-L)based on the integration of the distance view and the feature set view which are the views for similarity cognition.After the study of the relationship between the spatial data change and the similarity,a spatial data change detection algorithm for linear spatial data is developed,and a test for road data change detection is realized.
The paper analysis the decision support system of vehicle transport,logistics based on GIS;Then the paper presents twice spatial cluster algorithm and framework based on city road distance,and take example for tobacco enterprise.
It is important for cities to develop public transport system in order to solve existing traffic problems.In this paper,we propose a solution for complete route computing first we build two models-the bi-level public transport network model and the pedestrian network model,and then connect the two networks as one unified mixed transportation network based on which we compute the complete route.In complete route computing,first route is planned on the upper part of the transport network(Level2),then transport transfer solution is calculated on the lower part of the transport network(Level1),in the end pedestrian network model is employed for walking path guidance in the transfer area.Thus we can realize the complete route computing for traveling by public transport.
Node ranking is a promising area in complex networks researches.In this paper,a new node ranking algorithm based on topology potential is presented on the foundation of data field theory in cognitive physics,which can reflect the importance of nodes more precisely.An "axiom set" with natural language is established,which can concisely describes what the importance of node is.The approach of topology potential is more close to the "axiom set" than other approaches.In the end,the nodes are qualitatively partitioned using a hierarchical clustering method based on data fields.
This paper discusses the design of the optimal path Web services system in multi-level road network,the way of the data integration,the structure of the systems' server and client,and the expression of the workflow in system.A set of perfect design proposals is proposed.The application example is implemented to prove the rationality and efficiency of this Web services system,and it can practically solve the application question for the wide range road network analysis.
Based on the analysis of the transportation network design problem,the discrete transportation network design problem was discussed.The bi-level programming model was used to describe the problem,and the upper model considered the point of view of the transportation planner,in order to design the optimal network structure and achieve system optimal based on the restriction of budget,the lower model considered the user of the network and in order to attain the user optimal.The simulated annealing algorithm(SA) was used to solve the upper model and the gradient projection algorithm(GP) was used based on the path search to solve the lower model.The simulated annealing algorithm designed obtains satisfying result and has strongly robustness,which can solve large scale traffic network design problem.GP algorithm meets the essential characters of Wardrop equilibrium and gains more efficient by steady adding path.Application denoted the optimization method was rational,the result can improve the transportation status evidently,and the convergence speed of the algorithm is extraordinary rapid,so it provided scientific guidance for the decision-making of the transportation network planning.
Based on the study of conceptual modeling for nonplanar road network and GDF logical model,this paper sets forward a representation approach to modeling the urban multi-model transportation network and connectivity relationships between different features in different modes,and presents the formal definition of the involved features and relationships.A practical demonstration illustrates the application advantage of the presented model.The model also can be used to assist the automation of connectivity for urban multi-model transportation networks,and provide an effective support on public traveling information service.
A multi-level route-planning algorithm based on real-time traffic information in embedded environment is proposed in this paper,which can avoid some jam-packed roads at some extent in the embedded computing environment with the feature of small memory and low frequency CPU,and meet the requirements of real-time dynamic navigation application using traffic information.
Based on detailed discussion of the current status of geospatial information resources application and development of geospatial information technologies,this paper proposed a geospatial information service mechanism supported by multi-tier heterogeneous geospatial databases.By providing and calling WMS,WFS and other standard geospatial services built on distributed and cooperated databases,this mechanism provides a total solution for the state-wide geospatial data integration,sharing and services.
Scheme and key technologies for a new GIS based pavement maintenance management information system is introduced in this paper.The system applies modern and automatic instruments and equipments to rapidly acquire raw data of pavement condition.The data is synthesized to construct the pavement MIS data stock after processing,selecting and filleting,and realize GIS based the multi pavement data integrated management.
According to the demand of navigation data's production in our own country,as well as the features of multi-sources navigation data in vector form—especially the low frequent updating,the high repeated acquisition,and the heavy meaningless workload,this paper raised a feasible and effective method focusing on the integration of these data based on researching relevant data model,spatial transformation principle and related error evaluation theory,and supported the production and application of the electronic navigation maps theoretically and technically.
Requirements in urban transportation is increasing gradually and transportation network is becoming more complicated,which lead to the fact that the complexity of requirements modeling in urban transportation domain leaps accordingly.Meanwhile,how to aggregate existing service resources in an effective way and construct urban transportation information systems to satisfy personalized requirements become key issues faced by requirements modeling.Towards these problems,a context-aware and service-oriented requirements meta-modeling framework named RGPS is proposed in this paper by introducing corresponding contextual elements into the original meta-models.Then,a typical requirements use-case in urban transportation domain,providing trip plan for travelers,is demonstrated in detail to show how RGPS can support requirements modeling in application domain.
A new Kth shortest path algorithm based on bidirectional search is set forward in this paper.Based on the classical Dijkstra's shortest path algorithm,the presented algorithm conducts the path searching both from the source and destination nodes at the same time,and constructs the shortest path trees in positive and reverse sequence alternately so to populate several reasonable shortest paths between the start and destination nodes.The principle and implementation of the algorithm is described in detail and time complexity is analyzed.The efficiency and accuracy are verified with a real road network.
There appears to be a lack of temporal feature representation in classic dynamic segmentation.In order to meet the needs of representation of linear object with spatiotemporal feature,spatiotemporal dynamic segmentation method is proposed by adding temporal feature to classic dynamic segmentation.The author finally represents a traffic incident process by using spatiotemporal dynamic segmentation in ArcGIS.
The research is intent to study on how to determinate the ascription of the planar crossway section and the relative technology for define and expend its semantic mode when look the urban road as one certain spatial occupancy.The research starts at a series of the study on the road structure and relationship between roads in the crossway section and the spatial configuration of crossway.Then the article proposes use close-line to simulate road redline when visualizing selected heterogeneous road.The article also provides necessary solutions on the logistic model and data structure for that.
This paper proposed a pyramid-based cracks statistical method for pavement images on the basis of the consistence of pavement texture structure.After the enhancement process,it executed image segmentation based on multi-scale space algorithm,then the weighted pyramid-based cracks statistical was implemented on each segmented image,in the end picked up the cracked pavement images and achieved the objective of improving detection efficiency.Several experiments were executed aim at road sections with different pavement texture structure with this model,and the results demonstrated that it can pick up the cracked ones from massive pavement images correctly and effectively.
This paper mainly presents an off-line traffic sign detection approach.Because their color and shapes feature are very different from natural environments,the algorithm described in this paper takes advantage of these features.It has two main parts.The first one uses the feature of red boundary and white region to segment the image,and then fuse their segmentation image.The second one uses Canny operator to analysis the boundary shape and locate the traffic signs.Some results from natural scenes are shown.
In this paper we investigate K nearest neighbor searches in spatial network databases.A new algorithm for KNN queries is proposed.Based on the road network architecture proposed by Papadias et al.,we incorporate the precomputed NN lists into the algorithm for decreasing expensive calculation of the shortest path,and record the information of visited edges in the two lists for avoiding unnecessary disk I/Os.Experiments show that the algorithm outperforms other algorithms in high object density.