对象关系型GIS中改进基态修正时空数据模型的实现

The Improved Base State with Amendments Spatio-temporal Model in the Object-relation GIS

通过对几种典型时空数据模型特性的分析 ,提出了一种改进的基态修正模型 .此模型以空间数据的现状作为基态 ,从而避免了系统频繁载入现状数据的开销 ;同时 ,在对象关系型 GIS的支持下 ,该模型利用关系运算来实现“非起始”状态的随机整合 ,因而提高了系统的执行效率 .最后还从“时空快照恢复”、“时态拓扑分析”和“空间对象的历史沿革”等 3个方面阐述了此模型在对象关系型 GIS中的实现方法 ,并以大兴县的村边界变更为例给出了所提出模型在 Geo Media3.0环境中的具体应用过程 .经验证 ,此模型在对象关系型

It is difficult to neatly realize spatio temporal expression in traditional georelational data model for its complex organizing and storing on spatial data. But object relationship GIS simplify its complexity. Based on object relationship GIS, this paper puts forward the improved base state with amendments model, after analyzing some typical spatio temporal data model. This model takes the current state as base, and recorders the spatial objects' change procedure. All changes are reduced to 'add' and 'delete'. Because taking the current state as base, it could avoid the spending for the frequently loading current map. Because its special method of recording change, it would randomly and rapidly generate spatial data of any past time on the support of SQL. In this paper, this model is also expatiated from three aspects: recovering snapshots, analyzing spatio temporal topology and reasoning the change of spatial object. These techniques are realized in an instance about land use change under the support of GeoMedia3 0. The successful test indicates that it is simple and facile to realize the improved base state with amendments model in object relationship GIS.