Query And Visualize Multi-attribute Moving Objects

With the development of satellite positioning technology,wireless communication technology and mobile devices in recent decades,the location-based service is becoming popular and the moving objects database has attracted attention of many domestic and foreign scholars.Moving objects database plays an important role in traffic management,urban planning and social applications.However,many existing researches focusing on the spatio-temporal trajectories ignore the importance of attributes(such as speed,direction,color and size).The main work on multi-attribute moving objects is as follows:(1)According to the changes of attributes during the moving process,the attributes are divided into static attributes and dynamic attributes.We combine attributes data with trajectories data as multiattribute moving objects data and propose the representation of multi-attribute moving objects.In order to facilitate the management of multi-attribute moving objects in moving objects database,we introduce the method of the coordinate transformation,the extraction of dynamic attributes data and the formatting of dynamic data.We also complete the storage of the multi-attributes moving objects in the moving objects database;(2)In order to implement the query for similar trajectories of multi-attribute moving objects,we introduce the mapping method of multi-dimensional data to one-dimensional data and create the 4D RTree for multi-attribute moving objects instead of 3D R-Tree to filter the candidate results of the query efficiently.The influence of the number of attributes on the performance of query is analyzed and the influence of traditional 3D R-Tree and 4D R-Tree on the performance of the query is compared.(3)According to the defect of 2D visualization tool,we design a plan of multi-attribute moving objects 3D visualization.Using Java 3D technology,we develop a 3D visualization tool in the open source extensible database SECONDO.The positions of moving objects and the shapes of trajectories can be displayed in three-dimensional space.The movement of multi-attribute moving objects and the change process of attributes can also be displayed.Moreover,the visualization tool can also display the three-dimensional spatial structure of 3D R-Tree of moving objects,and it can evaluate the performance of 3D R-Tree by observing the spatial distance relations of the minimum boundary boxes of indexes structure.