电子海图单元索引结构的研究与应用

纸海图的索引在《航海图书总目录》中已经实现，为实现电子海图（ＥＮＣ）单元的索引，需建立一个索引结构，本文根据同种航海用途的电子海图单元之间的邻接关系建立网络图结构，根据不同种航海用途的电子海图单元之间包含与被包含关系建立多叉树结构，将这两种数据结构有机组合的索引结构结合散列查找法不但可实现电子海图单元的索引，也对ＥＣＤＩＳ功能的实时实现提供了有力支持

Study and Application of ENC Index Structure

The index of the paper charts has been realized in the Catalogue of Admiralty Charts and Other Hydrographical Publications, but ECDIS cannot use it to index ENC cells. To implement indexing ENC cells, this paper uses a network to describe the adjacent relations among cells which have the same navigational purpose, and uses multi tree to do the containing and contained relations among the cells which have the different navigational purpose. While being combined with the Harsh Searching Method, the index structure based on the network and multi tree can be used to index ENC cells effectively. Moreover, it specially makes good on the real time implementation of ECDIS functions.