Portable Electronic Map Meter Spatial Data Engine

The paper researches the Spatial Database Engine. First of all, the paper illustrates the concepts and the fundamental functions of SDE. Then it studies four primary problems. Those are spatial cognition model and data model, data index, geographic data storage and geographic data access objects.In the case of patial cognition model and data model, the paper illustrates three spatial cognition model several popular data models firstly. Then it puts forward data model basedof object-relational concept which satisfies the requests to store and manage data of great capacity efficiently.lt is data model of O-RSDE. In the case of data index, the paper generalizes several advanced data index at the present time and analyzes the feature of data index based on database emphatically. Then it illustrates the spatial ordering quad-tree index based on database of SDE. In the case of geographic data storage, the paper studies and tests several primary technologies, such as geographic data access model, the struct of geographic data table, attribute data of various geographic object. In the case of geographic data access objects, the paper illustrates the geographic data access class realized by oriented-object technology.This paper sumed up the following work in the end.