Figure 1

Modelling Structure and Function of Urban Systems. Left: Urban structural backbone of the 10 megacities considered here, as described from their street networks (data obtained from Open Street Map [68]). Middle: Urban functional networks described by the Foursquare data. The nodes are obtained by dividing the area analysed into cells of 500 m × 500 m. The edges are subsequent check-ins that might be between activities of the same type (intra-links: e.g. Food-Food, Tourism-Tourism) or different types (inter-links: e.g. Food-Tourism, Food-Sport). The collection of layers and inter-layer flows defines a multilayer network [4, 6, 7], i.e., a multidimensional functional representation of the urban areas. Right: The mobility flows between areas are captured as the edges’ weights. In the example, describing New York City, we can observe the different spatial distribution of flows between and across different activity layers (see also Fig. 5(a))