A bitmap index technology adapt to original TM/ETM+ image database

Abstract

Spatial database is an essential component of Geographic Information System (GIS). With the development of modern remote sensors and data acquiring instruments, the amount of spatial data increases with geometric series. Retrieval required data in such massive database is a challenging issue to database engineers. Therefore, building efficient index is significant to spatial database. In this paper, bitmap index technology, which is rarely used in spatial database, is taken into consideration. In this paper, TM/ETM+ images covered main land of China are selected to establish a spatial database. In order to rapidly inquire and retrieval required data from the spatial database, an effective spatial index is very important. A bitmap index solution for original TM/ETM+ image is advanced in this paper. The bitmap index schema, which indexes field by building 0 and 1 binary bit vectors, is designed based on analyzing its principle and applicable conditions. In the image database, the strategy is programmed to implementation and applied for data retrieval. So that complex querying operations can be transformed to bitwise logical operations. A users' interface is developed based on building such bitmap index for original TM/ETM+ images database. Then the paper probes into the bitmap index update mechanism to address problems resulted from inserting and deleting images operation. In order to address the problem of high cardinality, an encoded bitmap index technology is proposed as well. At last, a simple comparison and efficiency analysis is carried out to illuminate its applicability.