ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
265 
ition changes, 
lips, it can be 
scene change is composed of spatial property changes and change as a whole has its own properties, as given in previous 
spatial object changes, and at the same time spatial scene population change. 
:e of entities of 
:tion or occupy 
laving identical 
characteristics 
ims useful to 
jw entities by 
), reproduction 
itially identical 
lodification of 
a transmitter). 
Contagion is a 
Scene Change 
l 
▼ m 
Object Change 
1 
▼ m 
Property Change 
(Geometrical Properties, Dimensionality) 
Figure 1. Three levels of spatial changes 
everal entities, 
iy are splitting, 
single entity is 
>ize, location, 
i geographical 
)le entity and 
h changes of 
Geographical 
3.1.1 Spatial Property Change. We argue that primary spatial 
properties, in a visual sense, consist of location, distance, 
direction, shape and size. Location may be absolute or relative 
value of object in relation to a reference framework. Distance 
may be absolute or relative value between an object and a 
referent. Direction may be intrinsic, extrinsic or deictic. Size and 
shape are overall properties of a set of basic spatial units. 
Absolute size is measured with the number of atomic equivalent 
spatial units. Relative size is a partial ordering relation between 
an object and a referent. Shape is often described with contours 
(convexity, concavity, the chain of vertices), component 
approximation or compact ratios. Besides, in terms of 
geometrical dimensionality, spatial objects fall into three groups, 
point, line and area objects. Accordingly, we can obtain a set of 
primary spatial property changes, i.e., {location change, distance 
change, direction change, shape change, size change}, and 
geometrical dimensionality changes (point change, line change, 
area change). When geometrical dimensionality changes are 
combined with location change in set of primary spatial property 
changes, it turns out to be a set of moving object changes, 
{moving point, moving line, moving region}, by O. Wolfson, R.H. 
Gueting, et al (1997). Figure 2 shows a set of primary spatial 
property changes for a region object. 
998) proposed 
and a set of 
In conjunction 
ids of change 
ition between 
ransition, and 
single object 
mtinuing non 
reincarnation); 
; operations of 
mix); splitting 
5 on a single 
is of forming 
amalgamation 
>osite objects 
;ting an object 
jatial changes 
atial property 
i change and 
i is application 
e explained at 
>rm, we define 
object change 
ial distribution 
property and 
emantics with 
rete change, 
ge are spatial 
scene 
o geometrical 
lange. Spatial 
entity. Spatial 
Location change 
Distance change 
Direction change 
Shape change 
Size change 
Figure 2. Primary spatial property changes 
3.1.2 Spatial Object Change. Spatial object change is 
associated with object identity. According to mapping 
relationships between source objects and result objects, we 
define six kinds of spatial object change (Figure 3): 
1) 0:1 change, which indicates that an object is born. 
Equivalent words have existence, appearance, creation, 
birth, etc. 
2) 1:0 change, which indicates that an object died. Equivalent 
words have extinction, disappearance, destruction, death, 
etc. 
3) 1:1 change, which indicates that an object is transformed 
into other object. If source object is the same as result 
object, then the change is property change. Otherwise, the 
change is metamorphosis in (Kathleen Hornsby and Max 
J.Egenhofer, 1997, 1998). 
4) 1:m (m>2) change, which indicates that source object is 
divided into several result objects in the form. The source 
object may be included in the set of result objects. If all 
result objects are the same as source object in essence, 
then the change is reproduction. If one of result objects is 
the same as source object and others are different 
essentially, then changes may be spawn, splinter or 
production. If each result object is different from source 
object, then changes may be division, dissolution or 
secession. 
5) m:1 (m>2) change, which indicates that multiple source 
objects are aggregated into a result object in the form. If 
result object is the same as one of source objects, then