The paper, on the basis of a fifteen years experience in mapping urban areas from satellite images, with Landsat, Spot and IKONOS, for planning purposes, proposes a general working methodology in two phases: 1) the creation of a map of built-up areas; 2) the identification and definition of classes or typologies of built-up areas extracted in the first phase.An application to an area of the Veneto region exemplifies: 1) the variety of strategies, approaches, and processing techniques that may be used in the first phase, 2) two sets of spatial analysis techniques for the second phase, which includes computing local density of built-up areas and landscape indices. The paper discusses two general issues 1) the significance that the results of these processing assumes in different spatial scales; 2) the complex and articulate relationship between territorial descriptions and information acquisition and processing techniques.