基于MapObjects的快速图素选择算法

Fast Map-feature Selecting Algorithm Based on MapObjects

讨论了在基于GIS构件MapObjects的地理信息系统中,实现某些较复杂的图素选择方式遇到的困难,分析了造成困难的原因在于MapObjects的接口单一和过分封装.提出了通过派生、重载和加入辅助数据结构的方法解决该问题,弥补MapObjects的不足.在使用该方法时,针对MapObject本身接口单一导致的图素选择速度过慢的问题,提出了快速的图素选择算法,时间复杂度由O(m×n)降为O(m+n).经实验验证,效率提高极为明显.

To discuss difficulty in implementing map feature selecting in some complicated ways using GIS component MapObjects, and point out that the reasons for the difficulty are inadequate interfaces and too much encapsulation in MapObjects. A method is introduced to solve this problem using derivation, overloading and supplementary data structures. Due to the low speed of the method caused by inadequate interfaces in MapObjects, a faster algorithm is also provided. The fast algorithm can provides much higher efficiency than the original algorithm, which has been proved by both theoretical analyses and experimental tests.