Paper Title
Urban Composition: Case Study of Urban Planar Plots

Abstract
The goal of this study is to present a tool that permits to reduce the time of design and to obtain a quantitative assessment of the urban composition. The model is based on the modelling of the functions and the corresponding spaces into an orthogonal parcel having a planar form. The summation of all spaces that compose the parcel defines the surface called plot surface. The space of road into the parcel is a correlation of the shape and of the disposition of the plots, and of the number of plots in the urban Plan. The urban composition is characterized by a mathematical system composed by two equations represented respectively by the urban density and the site coverage ratio. This system is indeterminate because there is one unknown: the building footprint; and one correlation: the plot surface. To solving this problem, it is demanded to introduce a value density random and one value that corresponds to urban size, and after to compare the density obtained with the one introduced. This procedure uses the finite difference method. At last, the graphs illustrating the road ratio, the urban features are presented, and some recommendations about the using of the urban land in according with the sustainable development are proposed. Keywords - Land, sustainable development, urban density, functions, urban planar plots.