The Design And Implementation Of StarSDB An Embedded Spatial Database System

Along with the development of the micro processor, the performance of the embedded equipment has been improved rapidly. Embedded GIS is widely used not only in oil exploration, mine exploration but also very useful in military application.There are two ways to implement embedded spatial database system: C/S structure and plug-in structure. C/S structure consists of embedded equipment and large spatial database server. The C/S structure relies on the wireless network and it can not guarantee the reliability and quality of the spatial data. The plug-in structure extends the existed relational database system to support self-defined spatial data types, spatial index and spatial query functions. PostgreSQL/PostGIS are the typical realization of plug-in method. But the existed spatial data plug-ins are too complex to be running on embedded equipment. And the spatial database's size of them increases too fast that they can not fit the requirements of the embedded application.This paper designs and implements StarSDB an embedded spatial database system for the embedded military PDA. StarSDB is the spatial data source and the platform of the spatial query and plotting. This paper mainly researches and solves three problems:1.Researches and improves the OpenGIS's WKB format, designs an embedded WKB format for StarSDB.WKB is an exchange format for binary spatial data which is specified by OpenGIS Standard. But it is designed for the universal applications; it has a lot of redundant data. This paper makes two improvements to WKB: abstracts the endian and data type data of each spatial object. The test result shows that StarSDB's spatial database is about 50% smaller than PostgreSQL/PostGIS.2.This paper designs and implements an embedded spatial index middle-ware.According to the researches on popular spatial index technology and it's implementation, this paper presents the embedded spatial index middle-ware to implement the spatial index. The StarSDB's embedded spatial index middle-ware was designed all by interface class. It can be implemented on different database platform and by different spatial index by inheriting the interface. This paper implements the middle-ware on SQLite platform by R* tree spatial index. Propose DSQI(Directly Spatial Query Interface). StarSDB implements the spatial query by DSQI.3.This paper designs and implements Directly Spatial Query Interface DSQI.StarSDB implements fast spatial query by calling DSQI. The PostgreSQL/PostGIS extends the SQL language by self-defined spatial data types and functions that process the spatial data types. The user uses the extended SQL language to insert, delete and take the spatial queries. According to the requirements of the Military Plotting Software, implementing the spatial query and spatial data operation by SQL analyzer will cause complex system structure and much more time on analyzing the SQL language. So this paper suggests designing spatial query interface DSQI to operate on the spatial data. The test result shows that DSQI reduces about 50% of the size of the StarSDB and make improvement on spatial query performance.Finaly, this paper designed and implemented embedded spatial database system StarSDB. StarSDB is well enough for embedded software requirements and has fast response time.