ISPRS, Vol.34, Part 2W2, "Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
175
Table 5: Spatial relations between areas and lines
f d
-Ili!'''''
a b
disjoint
Table 6: Topological relations between points and lines
fc
ayj b
a r\b
a\b
alb
a Ah
Semantic
©
-0
0
-0
-0
-0
disjoint
-0
-0
-0
0
■0
contain
«
■0
-0
0
-0
-.0
contained
Table 7: Spatial relations between points and areas
fc
a uj b
a r\b
a\b
alb
a Ah
Semantic
-0
0
-0
-0
-0
disjoint
-0
-0
-0
0
-0
contain
•
-0
-0
0
-0
-0
contained
5.4 Topological relations between complex objects
The description of spatial relations among loop line objects has
been a difficult task and there is a lack of efficient solution. But
this kind of relations may also be distinguished with the new
approach. In order to describe this kind of relations, the value
of combination of dimension and connected number of (a 0b)
as well as the value of connected number of (a v 6b v ) is
employed. The result is shown in Table 8.
Table 8: Topological relations between loop line objects
(Fd,F„)
au b
ar\h
a\b
alb
a Ah
Semantic
Fn
a 1 w h 1 '
a r r\ b 1 '
!
a 1 ' / b‘
a 1 ' A h 1 '
<ci
U,2)
(-/.-0
O, h
0,1)
0,2)
disjoint
3
/
2
2
4
0,1)
(0,1)
O■ 1)
(U)
0,2)
interior meet
3
1
2
2
4
0,i)
(0,1)
0,1)
0,1)
0,2)
3
2
2
2
4
<:?>£>
O.l)
(0,2)
0,2)
0,2)
(/,4)
5
3
3
3
6
QD
0,1)
(0,2)
0,2)
0,2)
OA)
5
5
4
4
8
CO
0. h
(/. /)
0,1)
(/. 1)
(1. 2)
overlap
3
2
2
2
4
o
(>-U)
(’-¡.I)
(-A/)
(-/./)
(-1.1)
equal
2
2
-/
-/
-1
Using the new approach without other extension, the distinction
of complex relations between area objects can also be realised,
including various ‘inside’ relations. They are illustrated in
Figure 5.
(a)
(b)
(c)
(d)
Figure 5: Topological relations between area objects with
complex shapes
6. METRIC RELATIONS WITH THE SPATIAL ALGEBRA
Statistically speaking, ‘disjoint 1 relations prevail over other
relations. This kind of relations can, in fact, be considered as a
type of spatial order relations for the detailed description. In
most of existing models, there is no further distinction of
'disjoint' relation except for Chen et al. (20001). In fact, higher
resolution of 'disjoint' relation will be helpful for efficient
extraction of the desired spatial information from geographical
spatial databases. The 'disjoint' relation could be classified into
K-order neighbour relation according to the number of Voronoi
regions between two objects. Such K-order neighbour relation
is shown in Table 8. The operator to get the number for K is
called neighbour order denoted by l/', which indicates at least
how many Voronoi regions of objects an object reaches
another one.