Information visualization is particularly interesting in the applications of Urban Information Systems (UIS). Spatial visualization of urban data permits a detailed analysis of different informative layers, and a graphic synthesis of territorial information, as a great amount of data can be visualized through spatial indicators and spatial representations. Although, cartographic representations of urban data can be really complex for a non-expert user, as they present different levels of information simultaneously and in a multi-dimensional context. In this paper, we present a test in order to verify the potentialities and the efficiency of visual representation in urban contexts. To attend this objective we propose different representations of an indicator (the passenger flow in a subway system), using different combinations of visual variables (J. Bertin, 1967); then we evaluate the number of errors in the interpretation of the maps. The analysis of test results provides indications about preferences and difficulties found in the interpretation of graphic representations in urban contexts. Our research aims to prove that the use of “smart visualization” can be very useful for scientific, public and business purposes. It is and will be a more and more important tool in the management of information and communication expecially for the development of smart cities.