A Planimetric Model of Milan's Urban Master Plan

The process of development is described of a planimetric model whose purpose is twofold: the verification of total areas and standards in the Master Plan for Milan, and the creation of an urban land register for the city. Comparisons of the results of previous appraisals have demonstrated the necessity of moving from a purely graphical form of management (either manual or computerised) to methods based on planar maps, reinforced by the use of vectorisation techniques and automatic recognition of polygons. The paper is divided into three parts. In the first part the management problems arising from the process of urban change in Milan are outlined. In the second the concepts used to define the structure of data relating to the city, and to preserve the internal consistency of those data are illustrated. In the third part the algorithms used and the stages of work are demonstrated, from scanning of hand-drawn plans through to automatic construction and checking of maps.