Abstract This article reports discussion of different ways of describing and assessing urban form patterns, considering various approaches as figurative, geometric, and configurational, distinguishing between static and evolutionary descriptions. It also presents a case of urban form change pattern in more detail, in which methods originally used in statistical physics are applied. The case-study, the city of Santa Maria Brazil, explores the relationship between long term evolution of densification and expansion. The evidence suggests that such relationship is consistent with processes already described as self-organized criticality. Thus, as well as the majority of theoretical statements and analytical methods constitute references of scientific output of the Research Group “Sistemas Configuracionais Urbanos”, from the Graduate Programme of Urban and Regional Planning of the Federal University of Rio Grande do Sul.