ANNEX  IV

Absolute Urban Densities

Introductory note

From the data provided in ANNEX II on Urban Marathon, it was possible to calculate the gross densities for each threshold area (from 100 km² till 10,000 km²). As expected the steepness of the density gradient was differing quite a bit between these extra large cities. Except for “the Crater effect”, noticeable between 100 km² and 300 km² in a dozen cases, and a rather flat overall density in the first 500 km² in one or two other instances, the density is falling throughout the stages of the “Urban Marathon”.

Sources

Since the data on densities were derived from the ones on population and the area, the sources are the same as the one quoted in annexes I and II (the local, the national, and the supra national statistic offices, as well as the Wikipedia and city population websites).

Comments

Slow, constant decrease in absolute densities, make it hard to detect a considerable drop in overall density which may indicate the end of the city’s own hinterland (and the “acquisition” of some adjacent cities), and give us a hint where the natural limits of larger cities should be looked for. This is much easier to notice at ANNEX IV where marginal densities are presented.

Generally, densities are only in two instances (Mumbai and Manila) higher than 150 persons per hectare, at the 1,500 km² threshold, and in just one (Seoul) higher than 100 persons per hectare, at the 2,000 km² threshold. But due to already large population settled within this threshold it takes 3,000 km² more for the density to fall bellow the 50 persons per hectare mark (except in Tokyo and Jakarta).

On the other hand, since the thresholds were set rather wide apart, peculiarities of densities in those first couple hundred square kilometers are not as visible as they might have been if the thresholds were set more narrowly.