The mesoscale metereological models are the most used to study air quality and pollutant dispersion processes in urban areas. However they don’t have the spatial resolution to directly simulate the fluid dynamics and thermodynamics in and around buildings and other urban structures that can modify the atmospheric characteristics. In order to improve the quality and consistency of mesoscale models the most extensively adopted approach is the “Urban Canopy Parametrization” (UCP) which allows to describe geometric and morphological characteristics of urban agglomerations by a range of parameters derived from analysis of high resolution databases. This work has the aim to analytically determine some of these parameters and an automatic procedure has been implemented by Arcgis 9, using as input data the vectorial numerical geodatabase of the city of Rome, coded in 1:2.000 scale and provided by CARTESIA S.p.A. This procedure has been applied to the IX district of the city of Rome, whose full extent is about 8.1 km².