Interpreting the results of computerised methods in archaeology cannot be done without a reference to theoretical archaeology. The main aim of this paper is to discuss the theoretical assumptions behind the use of GIS and visibility analysis in modelling controlled territories. An underlying assumption is that changing locations of settlements are related to changing needs of communities in their environment. The relationship between visible areas and those needed for subsistence is reviewed in a specific context. The case studies presented are those of Nepi and Gabii. The different position these sites had in central Italian settlement hierarchies is discussed in relation with the interwoven relationship between assumptions on and interpretations of the results of visibility analyses
