Database Engine For Spatio-Temporal Process

The 21st century is "the century of the ocean"."Digital Ocean" is one important component of "Digital Earth". As a large oceanic country, China is urgent in this demand. The theory and technology of Marine Geographical Information System (MGIS) is the foundation of "Digital Ocean". Although it has been approximate perfect and has been applied widely the theory and technology of GIS in the terrestrial applications with the developing in the past 40 years, GIS's practice application in marine has began to develop formally since the 1990s. Because the marine data have the complicated spatio-temporal characteristics and comparatively the research of MGIS emerges recently. In result, there are some problems and difficulty on the manipulation of marine information when using traditional GIS, such as the basic expression of the marine spatio-temporal data, the storage of the large data set, and a series of questions to transmit the large data set and to display the dynamic data, and so on.Firstly, the paper expounds the development of MGIS, the present research status with its main problems. Secondly, combining the characteristics of the marine spatio-temporal process with the maturate technology of Spatial Database Engine, the article puts forward some methods on how to resolve the expression, storage and transmission by providing a database engine for the spatio-temporal process. According to the demand, the work adopts Oracle database to store the marine data. In order to transmit and exchange the data between database and the application program of MaXplorer, a MGIS software developed by LREIS, the article uses Oracle C++ Call Interface (OCCI) to develop the independent process engine. In the end part, this paper makes some researches on the relevant theory and technology of the process engine, and especially on the data model, which is the key foundation for the database engine. And based on the recent spatio-temporal data models, according to characteristics of marine point process, a data model for marine point process is designed. In order to improve the query speed, the work discussed the data index too.According to the above-mentioned theories and technologies, and comparing the relevant methods of Oracle application program, the article finally practises the process engine based on Oracle database with Microsoft Visual C++ 6.0 and OCCI. The experiment indicated that the scheme mentioned above is feasible.