This publication collects the results of a practical experience of survey, through the direct control of satellite images from high to medium resolution, over areas subjected to desertification problems. The problems of the local population are closely tied to the equilibrium in the management of the territory, which is compromised by the difficulties of maintaining traditional methodologies of management. The new survey technologies, based on the Remote Sensing and Geographic Information System, allow analyzing the details of the present situation and point out the dynamism of the phenomena and the impacts with anthropogenic activities.

However, the desertification in Africa has become an important problem in the Sahel area [10]. Thus, it is very important to carry out continuous scientific research as explained in [11]. The Algerian Ministry of Agriculture and Rural Development initiated several actions when desertifica- tion became a serious threat. ...

.. The government of Algeria has battled desertification by the following projects [12]: 1) Some vegetal walls were first established in the steppe in order to contain Sahara growth [8]. This program was kept until 1970 using an extensive reforestation policy forming the Green Dam [11]. The width of this vegetation defence was around 20 km and it was located in North of Sahara with the purpose of stopping the advance of the erg (zone with sandy moving dunes in Sahara) [11]. ...

... This program was kept until 1970 using an extensive reforestation policy forming the Green Dam [11]. The width of this vegetation defence was around 20 km and it was located in North of Sahara with the purpose of stopping the advance of the erg (zone with sandy moving dunes in Sahara) [11]. However, the main aim of this project was hardly accomplished, since that barrier is now reduced to a small number of aleppo pines. ...

This work becomes with methodological rigor a part of the innovative proposals for the characterization of the areas at risk of desertification. The complexity of the phenomenon of desertification, which involves extended surfaces in all continents, is one of the most alarming processes of the environmental degradation of our Planet and threatens the health and the living conditions of over a billion of persons.

The food crisis, in continuous increase, ask for the world of research to urgently supply reassuring solutions concerning the acquisition of indicators, which are easy to monitor and concur to control the phenomenon in order to fight its acceleration. The constant but different combination that determines the diffusion of deserti- cation in the territories, attributable mostly to climatic changes and the activities of the man, makes our job challenging and complicated, since it varies from region to region. We are aware of all this and therefore we think that the methodological approach of survey of the data is an extremely important element to locate of the phenomenon and to monitor its course.

Results of the NATO Advanced Research Workshop on Desertification and Risk Analysis Using High and Medium Satellite DataTozeur, Tunisia 9-19 December 2006
NATO Science for Peace and Security Series C: Environmental Security book series (NAPSC)