The Topology of Polygon A at Time TO
The Topology of Polygon A at Time T2
Poly-ID Arc-ID From To Poly-ID Arc-ID From To
y
A al TO NOW A al TO TI
A a2 TO NOW A a2 TO NOW
A a3 TO NOW A a3 TO NOW
A a4 TO NOW A a4 TO NOW
A all TI NOW
The Topology of Polygon A at Time T1
Poly-ID Arc-ID From To Poly-ID Arc-ID From To
A al TO T1 A al TO Ti
A a2 TO T2 A a2 TO T2
A a3 TO NOW A a3 TO NOW
A a4 TO NOW A a4 TO T3
A a5 T2 NOW A a5 T2 NOW
A a42 T3 NOW
The Topology of Polygon A at Time T3
Poly-ID Arc-ID From To
A al TO Ti
A a2 TO T2
A a3 TO TS
A a4 TO T3
A all T1 TS
A a5 T2 TS
A a41 T3 TS
A a42 T3 TS
The Topology of Polygon A at Time TS
Figure 4.1. The Representation of The Evolution of Polygon A in a Database
HIGHWAY-TOPOLOGY
ARC-ATTRIBUTE
B:
G:
Highway-ID | Arc-ID| From | To Arc-ID| Pavement y panes
H1 al TO |NOW al Good 4
H1 a2 TO T1 a2 Fair 2
H1 a3 TO | NOW a3 Fair 2
H2 a6 TO | NOW a4 Fair 2
H3 a4 TO | NOW a5 Good 4
H3 a5 TO | NOW a6 Fair A
Hl a2 | T1 |NOW a2 | Good 4
Figure 4.2 The Propagation of Time Attributes From One Relation to Another
5. CONCLUSIONS
The storage of historical geographic information is based
on the state and time topologies. The proposed framework
is a modified tuple-based time stamping approach. Since a
historical database manigement system (HDBMS) can be
used to manipulate the historical geographic information,
historical queries over time, as well as efficient data shar-
ing, data integrity, and data security can be provided by
160
HDBMS. The stored topological structures do not only
simplify and speed the spatial searching, but also trap the
data errors. This framework just records the changing
information. When a new state emerges, this approach just
records the new state, and amends the time duration of the
corresponding old state. Therefore, the data redundancy is
considerably reduced compared with the data version
approach used in the current GIS.
M
Sa
