Study On Multimodal-Supported Composite Transportation Network Model And Key Technologies

21th century is a century with huge transformation. City transportation is transforming from single mode to multimode. Shanghai Expo Transportation Research Organ has proposed building a multimodal and integrated moden transportation system. The Transportation domain is one of the most important and promising GIS application fields. Transportation network model has been concerned highly by International GIS-T academia and industry. With the progress of transportation multimodal, GIS-T data model should provide the composition modeling ability of multimodal, and also provide various network services, which will be a necessary trend and has very important reality significance.Combining the national 863 project named network-oriented vast spatial information of large-scale GIS, This paper focuses on the study of abstract and definition of transportation entities and transportation phenomena in multimodal-support transportation network, as well as relations between transportation entities and the network model expressed by multimodal chacteristic and probes into a series of modeling problem such as its conception model, logic model and physics storage and so on. On basis of the data model, this paper also study on key points such as multimodal-support network topology self-building technique, version-based topology update and maintenance technique, multimodal framework-based multimodal network analyzing algorithm to provide high efficiency network analyzing services for transportation and its related fields. The research works are as follows:(1) Retrospect to the development and actuality of multimodal transportation, deeply studying on various existing mature transportation network model at home and abroad, specifically analyzing and summarizing the advantages and disadvantages of different models, linking with the new characteristic of city transportation multimodal development, this paper points out the multimodal and integrated development direction of city transportation and sums up the research actuality of multimodal transportation network model at home and abroad, meanwhile anatomizes the problems underlying in multimodal network model research and application presently.(2) Researching on the holistic frame of multimodal transportation network model, according to research on picking up of primary transportation characteristic, abstract of transportation objects and its related phenomena and expression of transportation entities and relations between them, this paper brings forward a series of conceptions related with multimodal, puts forward an entity-oriented intelligent multimodal transportation network data model, carries through conception modeling and detailed designing from the way of transportation entity spatial feature model, transportation entity attribute model, transportation entity relation model, transportation entity rule model and multimodal characteristic support, and emphasizes on research and designing about how to supply modeling support of multimodal characteristic in the transportation network model which is able to satisfy modeling requirements of both single modal and multimodal.(3) Based on multimodal transportation network conception model, this paper gropes for the translation process from conception model to logic model and physical storing model, and stresses on the definition of data items and interfaces for each conception and the standardization and specification of transportation entity object in conception model, then expatiates on the logic modeling process. After completing logic modeling, this paper discusses how to meet the requirements of data structure and GIS-T network analyzing in the entity oriented multimodal transportation network model, designs the data structure from the factor of geometry, semantics, dissertation and topology relations, researches on data organizing and access methods in physical devices, spatial database storing strategies, relation model designing in spatial database and high efficiency data organizing and indexing methods, and implement physical organizing and storing of all the data entities in logic model in the computer eventually.(4) Researching on topology building methods of multimodal transportation network, this paper adopts the thought of geometry calculation, puts forward a geometry snapping model that support complex multimodal network snapping requirements, provides a flexible topology building mechanism and seeks for a bran-new multimodal network topology building algorithm which employ Hilbert curve hatching algorithm to accelerate topology building during network building, and this ensures the exactness and high efficiency of topology relation inside the single model, the correctness of the connectivity relation between models and roads built, the validity of connection between different independent model levels of the network, and the efficiency of completing the self-building of road connectivity relation inside a model and between models.(5) Researching on multimodal network topology update and maintenance strategies based on version management, this paper firstly studies the classic long transaction model of database and the state engine mechanism of multimodal network and illustrates version management theory and implementation methods, then discusses the different route network update complexion in multimodal model contraposing the possible transformation form of the route network in multimodal network, finally presents a doable solution which realizes the amalgamation of update and version management based on multimodal network and makes the maintenance of multimodal composite transportation network topology relation is implemented with the support of version management.(6) Research on various restrains circs of network analyzing of the multimodal network frame such as model changing restrains and time window restrains, this paper brings forward the content of network analyzing, searches after how to develop the existing single modal network analyzing algorithm into multimodal one Contraposing various restrain problems of multimodal frame, and develops MSP (Multimodal Shortest Path) algorithm based on level strategies and based on static time window on basis of the thought of existing single model algorithm, then extends the static algorithm to a dynamic one and studies the MSP problem based on dynamic time-dependent, finally discusses the actual application problem of various combination optimization of network analyzing based on MSP algorithm.In the end, the system prototype is built, and the experiment system-"MAPGIS7.0 multimodal transportation network analyzing system" which provides an executing environment for multimodal network topology building, multimodal network update and maintenance and multimodal analyzing algorithm is designed and realized. Meanwhile, the multimodal transportation network data model, the related theories in technique implementation, the methods of topology building, update and maintenance and network analyzing algorithm are compositve applied and validated, then the doability, validity and practicability of the model are proved.