GIS, satellite image and risks in urban and Peri-urban areas; methodological aspects

Abstract

Evoking the risk, even in urban areas, brings us back almost mechanically to the risks of flooding, or even silting up in certain regions. However, there are many other risks in cities that are still little or no explored using GIS solutions. We will mention in particular the problems encountered in the outskirts of cities and so-called sensitive areas, but also those due to the very configuration of certain neighborhoods (concentration of buildings, absence of support infrastructure) which generate risk situations. , or rather danger. Of course, we cannot overlook the problem of old neighborhoods that are abandoned in certain regions, but where populations still live and are exposed to multiple dangers following the continuous dilapidation of buildings. Finally, it is useful, even necessary, to also mention the perception of risk, which is sometimes extremely vague, in the minds of populations who end up generating their own risk themselves. In this article, we briefly examine the notion of risk, its perception in the collective mind and its consequences in everyday life. We then present, on a practical example, the contribution of GIS solutions and satellite imagery to the analysis and forecasting of risk in urban areas. The examples are taken from Algerian towns in the pre-Saharan zone. We will take the city of Laghouat as an example and we will develop the aspect of risk generation by the individual and society as a whole; we will also see how the local authority contributes to this situation of generation of risk or danger and, above all, how it can remedy it.