改进的时空数据基态修正方法

分析已有基于基态修正模型的5种数据存储方式,在此基础上提出多基态多级差文件修正方法、多基态单级差文件修正方法.与已有方法相比,提出的两种方法具有节省存储空间,历史数据恢复快而且不受历史久远影响的特点.多基态多级差文件修正方法与多基态单级差文件修正方法相比没有增加存储空间,但提高了数据恢复速度.讨论基态距阈值的确定方法,认为基态距阈值与时空数据库每次更新的目标数相关,更新目标数大时基态距阈值较小,目标数小时基态距阈值相对较大.

Improved Methods of Base state with Amendments on Spatio-temporal Data

Spatio-temporal data model is a hot spot in GIS, and base state with amendment is one of the most important data model in spatio-temporal data. Five kinds of existed data stored ways based on base state with amendment are analysed. The author proposed multi-base-states & multi-classes-deltafile with amendment, multi-base-states & single-class-deltafile with amendment. Comparing with existed methods, the two proposed methods save storage space with higher resuming speed of historic data and without length limits of history. Multi-base-states & multi-classes-deltafile with amendment is of higher resuming speed of historic data without increasing storage space than multi-base-states & single-class-deltafile with amendment. How to decide thresholds of base-state distance are also discussed. It is concerned with updated objects number. More updated objects number, less threshold of base-state distance; less updated objects number, bigger threshold of base-state distance.