Full text: The 3rd ISPRS Workshop on Dynamic and Multi-Dimensional GIS & the 10th Annual Conference of CPGIS on Geoinformatics

ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
3.1.3 Spatial Scene Change. Spatial scene is distribution of a 
set of spatial objects, but as a whole it has its own properties. 
Analogous to population by Pierre Gagnon, Yvan Bedard and 
Geoffrey Edwards (1992), for a spatial scene, its primary 
changes have location (position) change, direction (orientation) 
3.2 Detailed Time Semantics 
In time dimension, time semantics are enriched by three time- 
varying patterns, i.e., discrete change, stepwise change and 
change, shape change and size change (cumulative size change 
or population size change) and change of spatial distribution 
type (regular, random or grouped distribution), as shown in 
Figure 4. Spatial scene change is usually caused by changes of 
local objects. 
continuous change (Figure 5). Three time-varying patterns 
structuralize temporal data, certainly including spatio-temporal 
▲ i 
k ▲ 
• • 
► t 
► t 
Discrete Change 
Stepwise Change 
Figure 5. Primary temporal changes 
Continuous Change 
Ecologist James J. Gibson argued that events are perceived, but 
time is not (James J. Gibson, 1979). Time scale is generated by 
assigning time or date numbers to a sequence of events. For 
example, calendar corresponds to the rotations and revolutions 
of earth. It is known that geographical space psychologically is a 
large-scale space, whose configuration is apprehended by 
navigating through it. Large-scale space is larger than human 
body, and its configuration can’t be perceived from one vantage 
point (Montello, D. R, 1993). In analogy to the line of landmark- 
path-configuration cognition, we argue that human beings 
apprehend changes from property, to object, to scene. This 
conforms to human developmental cognitive rules of local to 
overall and part to whole. The changes of essential properties or 
most concerned properties result in the change of object 
identification. The changes of object properties and object 
identifications give arise to a scene change. 
Reginald G. Golledge (1995) argued that identity, location, 
magnitude and time are first-order spatial primitives, distance, 
angle/direction, sequence/order and connection/linkage are 
derived spatial concepts, spatial distribution (boundary, density, 
dispersion, pattern, shape), correlation, overlay, network, 
hierarchy and others are higher-order spatial knowledge. By 
contrast, we list location, distance, direction, size and shape as 
primary changes at the level of property, but categorize spatial 
changes into three levels, property change, object change and 
scene change. Some of our considerations are from cognition 
and computation. Usually in the large-scale geographical space, 
the distribution type seems to be a kind of configuration 
knowledge, which formed in the course of human cognition. 
More qualitatively, location seems to be a relation between 
figure and background. For example, the island is at the center 
of a lake. Distance is a relation between two points. For 
example, the department store is near to Laval University. 
Direction is recognized into three sorts: intrinsic direction, 
extrinsic direction and dialectic direction (Holly A. Taylor and 
Barbara Tversky, 1996). The front of a car is of intrinsic 
direction. The north of America is of extrinsic direction. “The 
cinema is to right of a department store” is of dialectic direction 
with respect to an observer. The inherent reference frame of an 
object, the reference frame of scene and observer are three 
basic factors to determine directions. For an object of some size, 
its location or distance or direction is often referred to its central 
point, but is unrelated to its size. For example, enlarging a forest 
stand, but remaining its central point, doesn’t mean the changes 
of location, distance, direction of the forest stand. Shape mostly 
describes the properties of boundary of an object, such as 
concavity/convexity and triangle/rectangle/eclipse. Generally 
corner points, curvatures, and compact ratio are used to 
measure the shape of an object. In computation, we can 
calculate the location of an object with its distance and direction, 
or calculate distance and direction with given locations, but we 
can’t decide which is prior to the other. In a parallel example, we 
are not sure of computing velocity with distance and time, or 
computing time with distance and velocity. That is because we 
don’t know, for velocity and time, which is first perceived so far. 
To some extent, we feel that three levels of change and primary 
property and object changes should be somewhat cognitively 
Motivated by application requirements and current theoretical 
work, this paper focus on studies of spatio-temporal semantics 
modeling in spatio-temporal databases. Following the time 
semantics of event-sequence, we attempt to explore primary 
spatial changes possibly involved in spatio-temporal databases. 
Specifically, we define spatial changes at three levels of scene 
change, object change and property change. At the level of 
property change, a set of primary spatial property changes 
(location change, distance change, direction change, size 
change, shape change), together with geometrical 
dimensionality changes (point change, line change, area 
change), are proposed. At the level of object change, we present 
six kinds of object changes in terms of mapping relationships 
between source objects and result objects. At the level of scene 
change, a few of integral scene changes and distribution type 
changes are posed. Proposed spatial changes, as the content of 
spatio-temporal semantic modeling, are expected to bring closer 
theories and applications of spatio-temporal databases. 
However, our work is still at a very initial stage. Much work is 
needed to do in the future, such as to seek more cognitive 
evidences to verify our spatial change categorization, to add 
spatial relationship changes to our change classification. It is 
commonly known that topological relationship is a kind of

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