International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
   
  
  
  
  
New York 
London 
Figure 4.Mega-Cities Built up Area 
The different patterns of urbanization in the selected mega- 
cities, especially those related with urban sprawl, in addition to 
the low resolution of the satellite images used (30 m pixel), 
cannot guarantee us optimum results regarding the detection of 
the built up area. It is necessary a further development to 
measure accurately the urban sprawl on a global scale. 
3.2 From “built-up” to “artificialized” land 
The development characterized with a scattered urbanization, 
especially when it is surrounded by urban green areas, can 
hardly be detected with accuracy, because of the lack of high 
resolution sensors. So, it is necessary to move on from the built 
up area to the concept of artificialized land, which is the land 
impacted by the urbanization. This concept seems to be better to 
understand and explain the magnitude of the process of urban 
sprawl in the contemporary metropolises. 
For this purpose, once obtained the final dataset of built-up 
areas, we aim to measure the degree of physical continuity of 
urban settlements grouping the patches of the built up areas 
between buffers of 100 meters. That built-up land, grouped at 
200 meters and aggregated in continuous urbanization, offers a 
relatively accurate image of artificialized land of the mega- 
cities, such as shows the accuracy analysis that has been done. It 
also allows the identification of the central continuum of each 
window, and helps to understand the structure and morphology 
of the studied world capitals. 
  
  
  
Maga-Cities Built-up Area Aggregate (Total) Aggregate (Central) 
Chicago 5.170,86 6.562,34 4.847,75 
Tokyo 5.257,05 7.481,97 4.904,78 
México DF 2.042,84 4.562,39 1.296,67 
London 4.433,02 6.330,16 2.383,10 
New York 5.022,22 9.104,47 6.913,74 
Sao Paulo 4.368,92 4.997,80 2.265,37 
Moscow 3.322,68 4.265,05 1.354,79 
Shanghai 4.470,51 7.287,49 1.967,79 
  
  
Table 1.Land Consumption 
Table 1 shows, the total of the artificialized land and the built 
up area for each window of the metropolises, and also the 
artificialized land for the central continuum of each metropolis. 
New York stands out with more than 9,000 sq. km of urbanized 
land, followed by Tokyo, Shanghai, Chicago and London, as 
the metropolis with highest level of land consumption. In 
contrast, Moscow, Mexico City and Sao Paulo have lower 
levels of land consumption, and thus of sprawl. 
  
  
       
    
   
  
   
   
Mexico 
Moscow 
HOD 
  
  
  
  
; A Sao Paulo ‘ HE : Sinai 
Figure 5.Central Continuum of Mega-Cities