对林业地理实体时空演变过程进行分析,认为林业地理实体的演变总体上是渐变和突变交替的时空过程,而且各专题属性和空间分布的演变类型和演变频率不尽相同。在此基础上,提出由序列快照和事件方法组合而成的序列状态时空表达方法,以状态集表达时空对象在生命周期内的演化历程,并针对林业数据的特点,采用面向对象的数据组织方式设计了林业资源时空数据模型。模型可对不同演变类型进行组合,并实现了对渐变和突变的统一表达,另外,模型也允许采用不确定数据以加强对渐变过程的表达。通过原型系统验证了模型的可行性。
There have no suitable spatio-temporal data model to manage dynamic data in forestry information field so far. The evolution of forestry geographic entity generally is a temporal and spatial course in which gradual change and abrupt change happen alternately. Furthermore, the type and frequency of evolution of spatial distribution and attributes in forestry geo-entity are not the same. A new spatio-temporal expression named sequence states which is composed by the methods of snapshots and events is put forward. ;n that basis, an object-oriented forestry spatio-temporal data model developed according to the characteristic of forestry data. Different types of evolutions could be expressed by thismodel aswell as different typesof changes. Moreover, uncertain data are adopted in the model to strengthen expression to the course of gradual change. The feasibility of the model is verified by a prototype system.