The cities are places where people, goods and information flows concentrate and, even if they differ in position, dimension and functions, they remain the main players of local, national and international development. Every city, even if represented by its "historic centre" - space that not always has maintained its role of principal central position in the urban evolutionary processes - has experimented developing areas of specialization and concentrations of functions, as districts marked by one or more dominant functions: commercial, administrative, residential or cultural. Starting from the definition of the Central Business District (CBD) or "central place" of the city and keeping as reference the "urban environments" or "districts" of the most recent town-planning project of the city of Sassari, we performed a quantitative and distributive analysis of the core urban activities of the whole territory of the Municipality of Sassari. Such analysis was realized on a point pattern represented by the spatial distribution of ‘high level’ urban activities and their elaboration by means of spatial indexes and density estimation. The spatial indexes, referred also to urban roads’ length and to the number of residents of every urban subunit considered, highlighted that such kinds of activities refer mainly to the city center area and concentrate in just four of the thirty-two districts. The GIS elaboration and processing allowed us to represent the central area (CBD), highlighting a core, as Piazza d’Italia, where a limited number of residents corresponds to a greater presence of rare activities.
