The Research And Application Base On The Improved R-tree Spatial Index

With the development of Geographic Information System (GIS),the research of spatial database has became more and more important. Although relational database can store spatial objects's data, but it does not support efficient access to spatial objects. The mufti-dimensional aspect of spatial data makes incompatible with nomal index in relational database. Search key in normal index is one-dimention-based, and is only suitable for indexing one dimentional data. Each dimention of spatial data is not in precedence to other, so special index is needed to support spatial data, which leads to the introduction of spatial index. Spatial index utilizes some kind of spatial relationship to organize data entries, with each key value seen as a point or region in a mufti-dimensional space. Due to the high complexity of spatial objects and spatial queries and also due to extremely large spatial data volumes,currently GIS is faced with stringent requirements on large data storage,effcient access method and fast query processing. Spatial index is a indispensable part of spatial database, and can dramatically improve efficiency when doing a spatial query. So, How to design proper spatial index structure is one of the most realistic, pressing and leading scope in GIS field. After addressing the related concepts of spatial index technologies and reviewing the development of spatial index technologies, this paper analyses the typical and efficient spatial index technologies especial as R-tree in detail. By analyzing and comparing the algorithms of various kinds R-tree spatial index technologies, this paper makes some improvement to the structure of R~*-tree specially.Afterward we discuss and analyze the performance of the improved R~*-tree spatial index .The result of research indiactes that the improved R*-tree has a better performance compareing to the original R~*-tree.Finally,we explore a system implement project for spatial query and establish a prototype spatial query system using the implement project which is base the improved R~*-tree. We summarize the research results and prospect the further work at the end of this paper.