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system with the least possible ambiguity [PHA 14]. This chapter focuses on two
large questions: (1) on the identification, construction and categorization of the
objects associated with the posed question; (2) on how to apprehend change, either
at the level of the objects themselves or at that of the attributes that characterize them,
of the relationships among them, of the processes that underlie them. The categories of
objects will be discussed from an ontological approach situated at the interfaces of
philosophy, computer science and geomatics (section 1.1). We will then discuss the
different ways of dealing with change of objects in time (section 1.2). The main
objective is to show the interest of an approach that allows moving from a sociospatial,
historical or environmental problematics to a conceptualization in terms of objects.
Most considerations are anchored in the operational area of management and analysis
of geographical information, but the objective is not to address the
operationalization of these designs in formal representation languages.
1.1. Different points of view on ontology
The first step consists of a start from an ontological point of view to discuss
“things” at stake during the description and modeling of a spatio-temporal question,
whether it is a social or environmental one. Ontology, the study of “the being as
being” according to Aristotle, must, therefore, allow specifying “things” that we
wish to study, whether from the conceptual or the empirical point of view (whether
database, statistics or simulation are considered). Before giving the definition that
will be adopted in this topic, we conduct a quick review of some definitions put
forward in the fields of philosophy, information technology and information
sciences, stressing the specificities that belong to each one of them. Different
categorizations that can be made about the “things” that we are studying are then
discussed, and an example of object construction concludes the first part of this
chapter.
1.1.1.
Defining ontology
Smith, a philosopher of Aristotelian inspiration, suggested the following
definition of ontology: “the science of what is, of the types and objects structures,
properties, events, processes and relationships in every reality domain .../... of what
could
exist” [SMI 03]. The use of this conditional, referring to “things” that have not
necessarily been observed, is essential when we place ourselves in a modeling and
simulation perspective involving artificial worlds. In computer science, Gruber
defines ontology as a “specification of the conceptualization of a given domain”
[GRU 93]. This definition is consistent with the previous one in the sense that this
“specification” consists of clarifying the objects, properties and relationships
mentioned in Smith's definition. While the latter refers to world “things” (“in every
