Fig. 6

Considering all spatial units within the urban extents of (a) Cape Town, South Africa and (b) Lusaka, Zambia, the population density score (POPscore) is plotted against the built score (BUILTscore). Spatial units are classified according to settlement type, as either being within an informal settlement (yellow) or not, i.e. all other locations (blue). The size of the circle denotes the proportion of spatial units with each combination of POPscore and BUILTscore values in the two settlement types.