  The methods of the space syntax have been the subject of extensive
discussion, and several techniques to identify the axis lines have been
proposed. The space syntax can be represented in terms of line graph, a graphs
defined on the edge of a given primary graph. By means of the line graph
algorithms, a system of labels defined on the edges of the primary graph is
transformed into a system of labels on the vertices of the line graph. The
contraction of adjacent edges with the same label allows to build a more
general graph than those generated with the methods of the space syntax. By
means of the functions implemented in Mathematica is therefore possible to
redefine the space syntax on any system of urban quantities (labels) and
reproduce the results of the axial lines as a special case. As an example is
discussed a possible application of the method to the urban noise analysis.
