A SIMPLE AND EFFICIENT SQL-BASED APPROACH FOR RETRIEVAL OF GEOSPATIAL DATA IN MOBILE GIS APPLICATION

摘要

The core objective of mobile GIS application is to provide vicinity geospatial information to the moving clients based on their current position. Since most of the mobile devices are limited in resources such as processing power, storage capability in terms of memory size, communication speed. Sending lot of map contents are normally required for all those applications as well. Therefore, the success of a mobile GIS application depends mainly on the efficiency of the geospatial data delivery method used and how well the adaptation can be employed. Two customised spatial index numbering schemes have been devised. Evaluation has been conducted in the actual mobile environment to determine the relative efficiency for this two numbering schemes. The main purpose for devising a unique spatial index numbering system is to provide a faster and simpler way other than using R-Tree algorithm to fetch the regularly geo-referenced map base images. A prototype mobile application is developed based on this customised spatial index scheme with an open source spatial-enabled RDBMS engine. The work flows and algorithms in the initial formation and subsequent updating process of the local dynamic moving geospatial database will also be described in this paper.