Research On Storage, Management And Application Of Change Information Based On Geographical Events

The construction and updating of geographical spatiotemporal database is the important components of the national spatial data infrastructure construction, its quality and current affect and restrict the analysis and decision-making results of all application systems. The substance of the spatiotemporal data updating is the process of spatial entity state change. The description, modeling, and storage of change information are very important in the whole updating process, how to describe and model and store and manage the change information effectively is the key words of storage, recognition and managing change information by computer, is the precondition of updating operation, and is also a key technique to query the historical change of the geographical elements. According to the characteristics of spatial data change information and the demand of the spatiotemporal modeling, this paper puts forward the geographic event model for spatial data updating, and make systemic and thorough research on the description expression and the storage management of the geographic events for the geographic event model, the main content is described as follows:(1) This paper analyzes the present situation and the development of the description expression and the storage management for the change information from the theory, technology and application, it puts forward the necessities of establishing the geographical event model, and also puts forward the corresponding technical process according to the characteristics of the spatial data updating.(2) This paper analyzes the change types of the geographical elements and the spatiotemporal change characteristics of the geographical elements in the digital map production processes, it defines the spatiotemporal change characteristics for the internal changes of geographical elements and geographical elements level changes. Take examples for settlement places, roads, rivers, this paper analyzes the change types of every kind of geographical element and the main factors of driving changes, it provides the foundation and the precondition for constructing geography event conceptual model.(3) This paper introduces the concept of geographical event to describe and store the change information of geographical elements. According to the characteristics of geographical events, this paper divides them into basic geographical events, complex geographical events, causal geographical events and evolution geographical events, and gives the concept and mathematical definition of each sort of the geographical events.(4) In order to describe the geographic events more effectively, this paper adopts the form of predication to describe and model the spatiotemporal process of geographic elements and relationship of the geographical events logically. This paper establishes the logical expressions of basic geographical events, through the constraints to constitute the basic geographic events, with that to judge the complex geographic events, causal geographic events and evolution geographic events. In view of the above logical expression process, this paper models by UML process, designs the corresponding physical storage structure and basic geographic event database to get ready for the subsequent geographical events in the application of the spatial data updating . (5) This paper establishes the relationship between the geographic events and the update operation, with the form of rules to guide the spatial data updating, and design the geographical elements change list. Combining basic geographical event list and geographical elements change list, it establishes the mechanism of the correlation with the geographical elements, geographic events and update operation to realize the bidirectional queries between the geographic events and geographical elements. This paper adopts and revises the ISO time frame, through adding an explicit time relationship to geographic event model to manage the history change information of the individual elements, so as to improve the query efficiency.(6) The application practice of geographic event model, this paper applies the correlative theories and researches to the system, so as to realize the functions of the spatiotemporal data updating, historical retrospect query, historical representation and statistical analysis based on the geographical event model.