ts and objects
x
dos Man ?d OC
s and objects
relations in GIS are
les of object shapes,
lation between two
ept and is thus often
(a)-(b)]. The simplest
'etween two objects is
he represented point
tween two capitals to
ries. But this method
ry is big and its shape
hen and et. al [1995,
ate metric relations
is to calculate the
een their sub-sets of
he general Hausdorff
ecial case of its fuzzy
‚ the object shape and
of ordering relations
elations. The ordering
ed by the method of
^hen and et. at., 1995,
GIS are mainly caused
data. Generally, the
ire not error-free, they
the errors of scanning,
erlaying, and etal.
ing the uncertainty in
nes and areas), we can
d by Chrisman [1982],
spatial object K, can
11996
*
g ef
|
Fig.3(b). Positional uncertainties of topologic relations
VU ; e
„BC e, (C
9
ac P A.
Or „9
Ó d, ed <d Ó d. e sd e
Fig.3(c). Positional uncertainties of ordering relations
be represented as K -K ®u(e) ,; Where- € is the, buffer
distance of error distribution and L(£) is the fuzzy
membership function derived by £ . As shown in Fig3(a)-(c),
spatial metric, topologic and ordering relations between
error £ -band generated objects will cause different kinds of
uncertainties.
3. FUZZY 9-INTERSECTION MODEL
3.1. 9-Intersection
For driving binary topological relations between sets, Egenhofer
et al., (1994) developed the 9-intersection model based on the
usual concepts of point-set topology with open and closed sets,
in which the binary topological relations between two objects,
K, and K, sin IR’ is based upon the intersection of K,'s
interior ( K? ), boundary ( CK, ),and exterior ( K, ) with K,’s
interior ( K? ), boundary ( CK, ), and exterior ( K; ). A. 3x3
matrix 3 , called the 9-intersection as follows:
KK KR Ka
Sy eK KS CK, CK OK IK. [1]
Kink" K, "CK Kin
By considering the values empty (0) and non-empty (1) in
equation [3], one can distinguish between 2°=512 binary
topological relations in which only a small subset can be
realized when the objects of concern are embedded
in IR’ [Egenhofer and Franzosa, 1991; Mark and et. al., 1995].
The beauty and simplicity of 9-intersection model come from
the fact that it can solve the topologic and geometric problems
by using the formal logic and algebraic methods. Since present
digital computers are very strong for logic and arithmetic
calculations, but they are poor for high level geometric and
topologic reasoning. So the 9-intersection model has the
potential abilities for automatically spatial and temporal
reasoning.
3.2. Dynamic 9-Intersection
For integrally deriving different kinds of spatial relations
between sets, Chen and et al. (1995, 1996) developed the
dynamic 9-intersection model based on the concepts of the
metric topology with open and closed sets and the
morphological dilation, in which the general 9-intersection of
equation [1] is extended as follows:
[K,eB(s)^K? [K,9B(s)P^cK, [K9B(e)l'^K;
San (€) TKOB(ENINKS AK, @B(8)INCK, AKOBENK
[K,9B(&)] ^K? [KOB(E)TN6K, [KOB(E)T ^K;
[2]
where the K, and K, are given two closed sets, the K,®B(e,)
means relevant morphological dilation by the closed ball B with
radius £, , and the 5$, (€, ) means dynamic 9-intersection with
9
G.j)
parameter £, from K, to K.. Based on the equation [2], we
can derive dynamic topological relations by using the different
parameter £,. In particular case, when €, =0, we have
K ®B(¢,)=K,®{0}=K,, then the dynamic 9-intersections
9
Gj
and et. al, 1995, 1996].
Sen (E,) coincide with the general 9-intersection 3, [Chen
3.3. Fuzzy 9-Intersection
For deriving different kinds of spatial relations between
uncertain sets, we can extend the 9-intersection model to the
fuzzy 9-intersection model as follows:
Fig.5. Space segmentation of dynamic 9-intersection model
107
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996