Research On Group Nearest Neighbor Query Of Line Segment In Spatial Database

Spatial database query is an important application in the field of spatial database.Traditional group nearest neighbor query research mainly abstracts query objects into points.However,not all spatial objects are suitable for abstracting as points to research in real life.For example,when querying the group nearest neighbor position of the major mountains,if it is abstracted as points,the query will produce greater errors,which will affect the query results.Therefore,spatial objects are abstracted into line segments,and the group nearest neighbor queries of line segments in spatial databases are proposed in this paper.The main research content of this paper is as follows:Firstly,this paper further study a method for line segment k nearest neighbor query in obstructed spaces.The STA_OLk NN algorithm is proposed in the case of static obstacle data set.The query process is divided into two stages,filtering data from two parts of data line segments and obstacles in an obstacle environment.In the process of refining,On the basis of the relationship between the line segments,obtain the corresponding distance representation method.After comparing the distance,the corresponding method of obstacle distance is presented and the final correct query results are obtained.This method makes up for the problem that existing nearest neighbor of line segments query can not be found in the obstacle environment.This paper further study the group nearest neighbor query method of line segment in obstacle space is studied,which resolve the problem of obstacle.In the filtering process,according to the properties of line segment Voronoi diagram and obstructed line segment group nearest neighbor definition,proposed pruning theorem for the data line segments,and OLGNN_Line_Filter algorithm is given.Further puts forward the pruning theorem of obstacles according to the obstacle distance of line segment definition,and OLGNN_Obstacle_Filter algorithm is presented.In the refining process,in order to obtain more accurately results,the corresponding refining theorem and refining algorithm STA_OLGNN are proposed.In the case of dynamic obstacles,the DYN_OLGNN algorithm is given.The algorithm is divided into two cases: obstacle reduction and obstacle increase.The corresponding decision strategy is given in different cases,and the influence of STA_OLGNN algorithm is discussed.This method solves the line segment group nearest neighbor problem of finding the exact position in the obstacle environment.