The paper deals with the formation of the urban space, analyzing the land ownership patterns in relation first to the socio-economic conditions of the owners, second to the applied building regulations, third to the urban features and the road network, and fourth to the housing conditions.A complex co-relation of the above parameters is the outcome of this research work, which illuminates the real conditions created by the specific post-Second World War conditions in the basin of Athens. For the support of this research, special measurements have been undertaken concerning the geometric characteristics of the urban space in a suitable number of sample areas in the above basin, comprising planned areas, as well unplanned squatter areas. This kind of approach aims toward the formation of realistic scenarios in analogous cases, according to the theory of incremental planning suggested by Charles E. Lindblom.