基于观察者方位的方向关系及其查询处理

Observer-Orientation-Based Directional Relations and Query Processing

通过分析观察者本身及其方位特点,在基于投影的模型基础上,首先提出了一种新的基于观察者方位的方向关系模型。然后结合新模型的特点,对方向关系查询空间建立了R*-树索引,利用拓扑学和矩形代数理论,提出了三步过滤法用以减少索引空间,降低了R*-树中矩形的重叠区域,减少了查询路径。最后给出了方向关系查询算法。实验表明,与传统的基于投影模型的查询方法相比,新模型的基于观察者方位的查询方法节省了I/O时间,提高了查询效率。

Based on the projection - based model and analysing characteristics of the observer and his position, we proposed a new model for observer - orientation - based directional relations, established an R ＊ - tree index for the query set. Using toplogical and rectangle algebra theorys, a three- step fiheration to decrease the number of objects for index has been presented, which will reduce the overlap region of the rectangles in the R ＊ - tree. Lastly, the algorithm of the query process with respect to the new model has been given. The experiments shows that, in applications involving observers, the new model outfonns the traditional one. Much I/O time has been saved and the efficiency of the query, has been improved.