Research On The Query Of History Topological Relationship Based On Event-semantic Model

Topological relationship is one important class of spatial relationships in Geographic Information System (GIS). It has a very important significance on the representation and storage of spatial data, the analysis of spatial query and practical application. It is often used as selection criteria in spatial query, especially in the field of GIS and image databases. The query efficiency of topological relations attracts the academic attentioa Current research on topological relationship focus on2D and3D space, but as a latest research direction it pays less attention relatively on the Temporal Geographic Information System (TGIS).History topological comes from the temporal and spatial variation (topology change) of the space objects in the timeline, in many temporal data model, the event semantic data model based on temporal information systems from the viewpoint of the temporal GIS express the semantic with time and event Event is the reason why object changes, the occurrence of events leads to the changes of physical state. Changes may include many aspects, such as spatial location, object properties, all changes are meant one thing:the old object disappears, the new object is born and linking them together will form a History topological evolution of objects. If you go along the timeline to record these changes, an event indicates a temporal and spatial variation,a region of dynamic spatial information can be reflected. In this process, t the event has a definite time and content, in such a data model, topology changes can be stored in the form of events together, then topological queries based on history time has become a possible.History topology query problem, called HTQP, is a temporal GIS with a widely used environment. It is also the key to express the procedure of topological evolution between different space objects. Traditional recursive methods on relationship tree ignore the mixed semantic information and the large-scale data processing during solving this problem, which leads a bad time effect.Paper discourses the research and development status of the current mainstream temporal data model, then describes the concept of topological relationships based on the temporal data model of event semantics. When TGIS environment is more complex, to improve the efficiency and reduce the use of time, an improved recursive method is offered to solve this problem which is based on separation process and data stratification. Experimental results show that new methods can do it better and lead less use of time on solving the complex History topology query problem.Innovation of this paper as follows:(1) This paper proposes a recursive query method based on "logical semantic separation". This method isolates the static and dynamic semantics of temporal events stored in the database, and gets the establishment of the correspondence between them, then builds the initial solution only based the dynamic semantic. It reduces the query space, turns the complex HTQP into a simple HTQP.(2) This paper proposes a recursive query method based on "data stratification". Using this method makes large-scale data into small-scale data. It provides a rapid entry and inspiration for query, which can skip most of the nodes to get the result set, reducing the scale of the problem queries effectively and improve the time efficiency.