基于二维哈希表的海量高程点数据去重算法设计

Duplication deletion algorithm based on two-dimensional Hashtable for multitudinous elevation points data

由高程点数据构建的不规则三角网(TIN)是地形图最基本及最主要的数字高程模型(DEM)。重复的高程点会使TIN构网过程中产生错误,不能生成TIN,所以在构建TIN前必须对原始高程点数据进行去重。本文改进传统的基于一维哈希表的哈希算法,采用二维哈希表对数据进行去重,在内存需求和运算速度上有较大优势,有着良好的时效性及准确度。

TIN is the most basic and main DEM of topographic map. The repeated elevation points cause error in TIN triangulation creation process, so before the construction of TIN, the repeated points must be deleted for original elevation point data. This article improved the traditional method which is based on the unidimensional Hash-table, adopted the two-dimensional Hash-table to do the duplication deletion. This method has advantages in the memory requirements and arithmetic speed with high timeliness and accuracy.