This paper discusses the spatial distribution of social structures in the Metropolitan Area of Porto Alegre in 1991 and 2000 (census years), using spatial statistical techniques with a geographic information system (GIS). These structures represent a social hierarchy of the metropolitan space from across the combination of labour variables. For this goal, I use a measure of spatial dispersion: the standard deviational ellipse which does show compactness and orientation of the distribution. The paper concludes with comments regarding the patterns and trends of the distributions