The underlayer spatial database of stadbsii is based on realms and supports dual grid techonology . it can express spatial object discretely and avoid the complexity of spatial redrawing . the underlayer support makes it easier to implement efficient spatio - temporal management and spatio - temporal analysis operations Stadbsii系统的底层空间数据库以realms为基础，同时采用了双网格技术，在离散表示空间对象的基础上避免了复杂的空间调整，为实现高效的时空存取以及时空分析操作提供了底层保证。
