In resent decades, land use and land cover changes (LUCC) have attracted considerable attention within the scientific community initiating an international debate among scientists, experts, policymakers, non-governmental organisations and various economic and institutional players with some interest at or involvement in land use allocation (Parker et al. 2003; Verburg and Veldkamp 2005). A rapid and unprecedented transformation of the landscape is under way in almost all over the world. Urban development is consuming land and natural resources at an increasing rate (Geoghegan et al. 1998; Lambin et al. 2000; Wilson and Lindsey 2005), raising serious concerns about the sustainability of current economic-growth patterns, the quality of urban space and the state of natural environment (Briassoulis and van der Straaten 2000; Walker 2004a). Agricultural land, forests, natural areas and open space are given to urban development and poorly planned (if at all) urban patterns appear threatening the quality of life in numerous ways (Fekade 2000). However, ignoring past and current urban sprawl trends is not sensible, especially when those trends affect the foundations of human socio economic system. Greece has experienced urban sprawling processes for some decades so far (Leontidou et al. 2001).
Land use changes in Greece have been the outcome of combining forces with mostly economic, socio-cultural and institutional origin (Leontidou et al. 2001; Potsiou and Ioannidis 2006; Xinomilaki-Papaelia 2004). During the last 50 years, growing demand for urban (mostly residential and industrial) space has resulted in unplanned residential development and illegal dwelling construction to the expense of agricultural and forest land uses. This situation, tents to become an acute problem with serious economic, social and environmental implications (Karathanassi et al. 2003; Tounta 1998). Impacts are great and pressuring ranging from landscape aesthetic deterioration, biotic diversity threats, desertification and forest and open land "squeeze" to increased vulnerability to human settlements and local water contamination.
The negative environmental costs and externalities threaten people's health and urban and regional development perspectives. If we were to obtain monetary estimates of the externalities due to informal settlements, then the phenomenon could justify the adoption of upgrading schemes (Ferguson 1996) and the initiation of a land use planning process to reduce land invasion pressures (Abbott 2002).
Efforts to contain sprawl and revitalize older neighbourhoods through smarter growth practices, legislative initiatives and land use planning schemes have been contentious especially during the last three decades (YPEHODE 2006). The most well-known initiative was that of "The Urban Renewal and Reconstruction Project" curried out from 1983 to 1994 in a national scale. This initiative was an enormous project targeted at identifying the real urban space all over Greece. Moreover, the ultimate purpose of the project was to integrate informal settlements into the existing urban plans providing at the same time, the necessary public infrastructures and social services. Around the country, from the large metropolitan concentrations of Athens and Thessaloniki to the smaller rural municipalities, numerous land use planning initiatives attempted to lower the pace of urban sprawl (Katochianou and Theodori--Markogiannaki 1989) and integrated unlicensed residential constructions to the existing urban system. Concurrently with the planning initiative, several pieces of legislation were introduced in order to discourage further expansion of illegal housing. However, the results of such a policy do not seam to have been encouraging. Till now, the illegal housing phenomenon proceeds at a high pace, so that about 3.000 new unlicensed buildings each year (almost the size of a small town) get legalised and integrated into the existing urban system (NSSG 2000). …