Systèmes d'information géographique. Dossier ... - CiteSeerX

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expected from it. That is why any sizeable implementation always needs some phases of
analysis prior to the results.
The cost-profit analysis of the use of digital information is one of the other gambles which
have mobilised a great deal of energy without as yet being solved (see Chapter in the
bibliography). This type of question really took shape some years ago, at the same time when
faced with the size of the costs for gathering information, and as a result of failures in the
implementation of spatial information systems for which the balance of the investments
compared to the profits of the application were negative. Some attempts have since been
made to formalise the principles for the economic assessment of the introduction of digital
data in the processing of localised information. It was first carried out in the United States
(Dickinson and Calkins, 1988), this type of study has found an opening in France with several
works now published (Didier, 1990 ; Didier and Bouveyron, 1993).
Even if these attempts have undeniably contributed some new elements for understanding
the domain, it must be said that some years back these attempts were still incomplete, due
to the fact that they were too theoretical or not complete enough to be able to form an
accurate basis for assessment (Wilcox, 1990) 13 . Once again, geographical information
rebels against a robust formalisation of the principles for its use. In the cases of public
services, the problem is complex because the idea postulated is not only that of financial
profitability but also that of social utility, still badly perceived today.
GIS AND THE LEVEL OF APPREHENSION
IN THE URBAN TERRITORY
Does opening-up urban GIS to more thematic applications than before allow an improvement
in the operational results arising from the processing of digital information to be envisaged ?
The main pitfall comes once again from the types of data available in these "new formula"
UDB. Are they different from those that used to exist, and if so, to what extent may they be
used in strategic decision-making ?
M. Wolf (1993), underlines, and rightly so, that currently data stored by the towns come in
three different types : "natural" data (site, subsoil, landscape restrictions etc.), which is an
obligatory step to be taken into account, with environmental concerns ; "artificial" data which
are all the infrastructures built in the town ; and "intangible" data which are in fact the
indicators on the inhabitants of the town.
Nowadays the swap to information systems software allows these different types of data to
be collected and stored in the same working environment. However, the technical
performance does not guarantee optimum use, and every expert in urban planning today finds
himself faced with the methodological adjustments needed for combining "natural" and
"intangible" data in the analyses.
The urban authorities are in a special position, at the crossroads of the needs for technical
management and strategic decision-making for planning. The fundamental question that
urban analysis is faced with when using GIS is linked to these different levels of decisionmaking,
and the impacts that it has on the policies for collecting and using information.
13 A discussion broke out very early in the USA concerning this problem, causing an exchange of viewpoints in
IJGIS (Dickinson & Calkins, 1988, 1990 ; Wilcox, 1990).