Slide 20 of 29
From Worboys’ book (dates updated).
This shows the bitemporal regions associated with each road segment from the road planning example. Thus to the system in 1995, the segment ef did not exist at any valid time, but in 1996 the information had been entered that showed its existence from 1996 onwards. But in 1997, this information had been revised to show it existing only from 1998 onwards
There are topological analogies to those in 2D space, which produce an allowable set of predicates and queries: the set of concepts we have been looking for which we need to produce useful systems.
