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

Chen, Jun

Bibliographic data

Monograph

Persistent identifier:: 856566209

Author:: Chen, Jun

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

Sub title:: May 23 - 25, 2001, Bangkok, Thailand

Scope:: VI, 434 Seiten

Year of publication:: 2001

Place of publication:: Pathumthani, Thailand

Publisher of the original:: AIT

Identifier (digital):: 856566209

Illustration:: Illustrationen, Diagramme, Karten

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: PRIMARY SPATIAL CHANGES. Hong SHU, Christopher GOLD and Jun CHEN

Document type:: Monograph

Structure type:: Chapter

ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 The motion vector aims to support continuous change modeling, to facilitate future queries, and simultaneously to reduce data storage volume. MOST model makes possible real-time update of spatial locations of object, but it doesn’t emphasize keeping the whole history of spatial data. In contrast, Erwig, M., R.H. Gueting et al. (1997) designed the abstract data type of moving object into their geo-relational algebra. Extended geo-relational algebra has formally defined two abstract data types of moving object (moving point mpoint and moving region mregion) and relevant operators. The types mpoint and mregion are defined as mappings from time to space mathematically, that is, Mpoint time ->point Mregion: time ->region The type mpoint indicates that the location of object is varying over time. The type mregion indicates that extent of object is varying over time, e.g., shrinking or expanding. The authors insist that moving line is the trajectory of moving point, so it is somewhat unnecessary to define moving line type. In contrast to MOST model, extended geo-relational algebra put special emphasis on history maintenance of time-varying spatial data. Another difference is that MOST model pays more attention to implementation with motion vector data structure, but extended geo-relational algebra mainly focuses on conceptual abstraction of time-varying property of geographical objects. It is obvious that both MOST model and extended geo-relational algebra classify spatial changes by the joint criterion of geometrical dimensionality and location movement. 2.4 The Criterion of Spatial Variables Pierre Gagnon, Yvan Bedard and Geoffrey Edwards (1992) categorized spatial changes into three groups: one-entity change, two-entity change and multi-entity change. One-entity changes consist of existence, extinction, location (position) change, direction (orientation) change, shape change and size change of an entity. Two-entity changes consist of spatial relationship (topological relationship) changes between two entities. Multi-entity changes are population changes formed with 3 entities or more, including location (position) change, direction (orientation) change, shape change and size change (cumulative size change or population size change) and change of spatial distribution type of a population. The cumulative size is the summation of all individual sizes of entities of a population. When combined with the number of entities, it provides “presence rate”. The spatial population size corresponds to the size of distribution area, when combined with the number of entities, it provides “occupation rate”, and when combined with cumulative size, it provides “spatial density”. There are three types of spatial distribution, regular, random and grouped distributions. This change classification is referred to be based on the criterion of spatial variables, spatial variables of a single entity (location, direction, shape and size) and spatial variables of multi-entity (cumulative size, population size and spatial distribution type). 2.5 The Joint Criterion of Spatial Variables and Geographical Functions Christophe Claramunt and Marius Theriaut (1995, 1996) posed three types of spatio-temporal process: (1) the evolution of a single entity; (2) the processes involving functional relationships between several entities; (3) the evolution of spatial structures involving several entities. For the evolution of a single entity, there exist three types of process: • Basic processes including appearance, disappearance and spatial stability to allow representation of attribute variation without spatial effects; • Transformation processes involving changes in shape or size, including expansion, contraction and deformation (shape modification without size change); • Movement processes involving only position changes, including displacement and rotation. For the processes involving functional relationships, it can be grouped into two categories: • Replacement processes involving a sequence of entities of comparable types that accomplish the same function or occupy the same position in space (without necessarily having identical locations), e.g., succession and permutation. • Diffusion processes involving a transfer of characteristics between two or more spatial entities. It seems useful to distinguish between production (creation of new entities by actions of one or more entities of different natures), reproduction (creation of new entities by actions of essentially identical entities called parents) and transmission (modification of characteristics of a receiver due to influence of a transmitter). Each process carries a precedence constraint. Contagion is a specific form of diffusion. For the evolution of spatial structures involving several entities, three restructuring processes are introduced. They are splitting, union and reallocation. It is easy to know that the change classification of single entity is mainly based on spatial variables (shape, size, location, direction), and functional relationship evolutions on geographical functions. Also, some basic processes of single entity and spatial structure evolutions are associated with changes of object identity 2.6 The Joint Criterion of Entity Identity and Geographical Functions Kathleen Hornsby and Max J.Egenhofer (1997, 1998) proposed a change classification based on object identity and a set of operations that preserve or change object identity. In conjunction with geographical functions, they defined four kinds of change (or operation): (1) transitions (concretely, transition between object existence and object extinction, issue transition, and separate transition); (2) identity operations on a single object (creation, destruction, continuing existence, continuing non existence, and equivalent reincarnation, same reincarnation); issuing operations (spawning and metamorphosis); operations of combining single objects (merge, generate and mix); splitting operations (splinter and division); (3) Operations on a single object and a composite object, i.e., operations of forming composite object (aggregation, compound, union, amalgamation and combination), operations of splitting composite objects (secession and dissolution); (4) Operations of selecting an object or a portion of an object. 3 PRIMARY SPATIAL CHANGES From the above investigations, we can see that spatial changes are usually described in four respects, i.e., spatial property change, object identity change, spatial distribution change and functional change. Among them, functional change is application dependent, and is of various number, which can be explained at different levels of abstraction. Thus, in a general form, we define various changes at three levels, property change, object change and scene change. Scene change is similar to spatial distribution change, which is an overall change composed of property and object changes. Meanwhile, we recognize time semantics with three simple time-varying patterns, i.e., discrete change, stepwise change and continuous change. 3.1 Three Levels of Spatial Change In the bottom-up order, three levels of spatial change are spatial property change, spatial object change and spatial scene change (Figure 1). Spatial property change refers to geometrical property change and geometrical dimensionality change. Spatial object change is related to change of object identity. Spatial

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