基于Petri网的多重表达模型及其更新机制研究

地图的增量更新将时空模型与多重表达模型联系在一起,而已有的数据库模型从两者相分离的角度出发,既缺乏保存多重表达历史数据的机制,又不便于多重表达的增量更新。该文在总结时空模型与多重表达模型发展规律的基础上,以Petri网为数学工具耦合时空模型与多重表达模型,提出基于Petri网的顾及地图增量更新的多重表达模型,实现多重表达与时空变化的统一描述,为多重表达建库及其增量更新提供科学依据。

Multiple Representation Database Model Based on Petri Net and Its Updating Mechanism

Multiple representations and its incremental updating method put up difficult in cartography.It is necessary for cartography incremental updating to associate multiple-representation model with spatiotemporal model.However,the existing models cannot look after both sides.As a result,it is difficult to save and update the representations of the historic data.In this paper,a multiple-representation and its incremental updating model are presented and coupled with the spatiotemporal models by Petri net.As it is known to all,Petri net includes four parts:place,transition,arc and token.In the multiple representation and its incremental updating model,one place may describe one representation or state,one transition may describe one event or change,one arc links one place and one transition.Thus,the multiple-representation model and the spatiotemporal data model can be described in the unified and formal way.In the future,the model suggested in the paper will be applied to the basic scale map data.