When performing a search with MX-CIF quadtree, all the objects in the nodes which intersect a search-window will be taken as primary results, and then relations between the primary results and search-window are judged by an exact query. The amount of primary results is an important factor to affect time cost of query. This monograph inspected the advantages and drawbacks of the original MX-CIF quadtree compared with other structures, and proposed an improved MX-CIF quadtree which reduces the time cost of query by decreasing the number of the primary results in planar environment. The...