摘要
根据GML数据查询的需要,在分析XML文档编码和空间索引技术的基础上,提出一种基于扩展的元素区间编码的GML索引方法.首先通过扩展的区间编码方法对GML文档中的元素、属性、文本、几何体等要素进行编码;其次依据元素编码算法并将非空间节点、空间节点、元素节点从GML文档树中分离,产生元素编码序列;在此基础上根据节点类型的不同对属性和文本节点建立B+树索引以实现值查询,对几何体节点建立R树索引以实现空间数据的分析操作,并在查询处理时通过查询优化算法避免不必要的节点的遍历,进一步提高查询效率.实验结果表明,基于元素区间编码的GML数据索引方法是可行的、高效的.
According to the demand of data query of GML, a GML indexing method was proposea Da.~eu on extending the element interval coding, and analyzing the XML file coding techniques and spatial inde- xing method. Firstly through extending the interval coding method to encode the element, attribute, text, and geometric object in GML file. Then the non-spatial nodes, spatial nodes, and element nodes were sep- arated from GML file tree to generate sequence of element coding based on element coding algorithm. On this basis and according to the difference among the nodes, a B＋ tree index was built up for attribute and text notes to realize value query and a R tree index was built up for on geometric object note to realize spa- tial data analysis, and by means of query optimization algorithm the unnecessary overall query of the nodes was avoided, so that the query efficiency was further improved. Experimental result showed that the inde- xing method based on the dement interval coding was feasible and high-efficient.
出处
《兰州理工大学学报》
CAS
北大核心
2013年第3期88-93,共6页
Journal of Lanzhou University of Technology
基金
甘肃省自然科学基金(ZS031-A25-015-G)
