Geoscience Reference
In-Depth Information
- the mobilization of a great diversity of sources, tracking sensors, census,
surveys, archaeological dig etc.;
- underlying conceptual options especially according to the different ways of
integrating time and space;
- the different categories of change;
- the objectives and the different involvement of the four challenges as they were
defined in section 2.1.
In all the examples, the description focuses primarily on the first two challenges,
namely the construction of the objects and exploration of their evolutions. The other
two challenges are only presented in a concise manner because they are the subject
of the two following chapters. The examples do not have the same length, the idea
being to address a diversity of cases. Some are longer because they are better suited
to illustrate many of the points listed above, while others are present to illustrate a
challenge treated in an original manner.
2.3.1.
Cities' dynamics: construction and follow-up of composite objects in time
Urban growth is a particularly interesting case because it illustrates well all the
challenges that may arise in the construction process of a complex object, going
back and forth between conceptual and empirical choices. It is typical of objects that
are not defined in an unequivocal manner [OPE 81].
The example that is presented here is inspired by several projects that may be
brought together
7
: particular emphasis will be placed on the problematics of
definition and measurement of the city at the European level. To illustrate these
different forms of representation and modeling, we will briefly introduce the other
challenges that this problem has led to, namely the exploration and analysis of the
dynamic database, hence constructed, and finally its use in the context of simulation
models of urban dynamics.
2.3.1.1.
Step 1
:
to build a set of objects coherent in space and time: a harmonized
database of European cities
This question, raised at a very operational level, presupposes, however, that it is
possible to define an ontology of the “European” city. Such a challenge calls for a
dialog between the conceptual and empirical levels. As has been said in Chapter 1,
7 This example is drawn from multiple experiments led by Bretagnolle: - ANR Harmonie-
cités (http://www.parisgeo.cnrs.fr/spip.php?article38&lang=en) [BRE 11a]; - ESPON DB
program - urban data [BRE 13] (http://www.espon.eu/main/MenuToolsandMaps/
ESPON2013Database/).
