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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
STDB, and a change in the real world should have a (and only
have a) dynamic operation to deal with the operand. From the
object-oriented STDB management point of view, the operand of
dynamic operators is single entity (or single object), the mutation
between entities should be realized by the dynamic operation of
single objects. Based on this cognition, a complete set of
dynamic operations of STDB is presented based on the explicit
description of change with respect to the real world and the states
of existence and non-existence for identifiable objects in STDB,
which include 8 current data’ dynamic operators and 8 history
data’ dynamic operators [ZHOU Xiaoguang, CHEN Jun, et al,
2003b]. The 8 current data’ dynamic operators are Create,
Ex-create, Destroy, Con-eliminate, Eliminate, Se-modify,
Sp-modify, Reincarnate. All of the 8 current data’ dynamic
operators except Destroy, may be used in the updating process.
5. EVENT- BASED CHANGES OF PARCELS
As the preceding, the spatial changes of the split, union, and
Modification of the common border events can be determined
by the events and the topological relations between involving
entities. Usually there are only 1 to 2 zones (and it’s components)
involved in such events, these events occur more than 5094
[Effenberg, W. W. 1996]. According to our study on
CHANGSHA city, among these events, the split event occurs
most frequently. Split event will be used as an example to
illustrate the updating method of EBIU-CDB in this paper. At
first the changes of splitting are studied.
Split means division of a parcel into 2 parts. 2 fundamental
A
parcels showed by Fig.3 can be involved in split event. In split
process, a new edge (border) has to be inserted. It is assumed that
the start node is nl and end node is n2, the inputting edges are 11
(and 12). The simple parcel A split to simple parcel B and C; a
parcel with one hole A split to C and D.
There are 7 cases in the split of parcel: (1) the simple parcel
division into 2 simple parcels (Fig.5 (1)); (2) the simple parcel
division into a simple parcel and a parcel with one hole (Fig.5
(2)). (3) the parcel with one hole A division into a simple parcel
D and a parcel with one hole C, C meets D (Fig.5 (3)); (4) the
parcel with one hole A division into 2 simple parcel (Fig.5 (4));
(5) the parcel with one hole A division into a simple parcel D and
a parcel with 2 holes C (Fig.5 (5)); (6) the parcel with one hole A
division into a simple parcel D and a parcel with one hole C, C
meets B (the hole of A) (Fig.5 (6)); (7) the parcel with one hole A
769
division into a parcel with one hole D and a parcel with one hole
C, D*include B (Fig.5 (7)).
T A i4
T. B
blu
: (2) A=A", nl=n2
(1) A=A , n1#n2
TI
BA la” AA”
zu = d
r2 d C D
(3) nl #n2 C40 HNBA # ©
18 A^ I2n8A' 2 ®
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12N0B xo
C b C
FE
B a B D H a
11
SéUni=n?
5iinlzn2 poni ii “77 'nl=n2
: D-D .
INGA = D include B
tine Bo Xe:
Fig. 5 the splitting of a parcel
6. THE UPDATING ALGORITHM OF SPLIT EVENT
Whenever a split event occurs, the following actions are
triggered automatically (Fig.6): (1) Extract the data of split parcel
(include nodes, edges, and region); (2) Input the coordinates of
the new edge (11 or 11 and I2); (3) Determination the change type
according to the shape of the involved parcel and the relationship
between the inputting edges (or arcs) and the involved entities: it
is assumed that CASE 1 to CASE 7 is corresponding to the
changes 1 to 7 showed by Fig.5. (4) Edges (or arcs) will be
reconstructed if necessary, new parcels will be built: (5) the
updating operation expressions will be formed; (6) the database
updating operations are executed to update the records in the
database; (7) semantic attribute of new entities will be asked to
input; (8) the consistency of the involved records will be checked
according to the consistency rules. If