VALI-URB - Urban sprawl and ecological corridors: Consolidation of VHRS remote sensing methods

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Context and objectives

To manage both the urban fabric and the green network, regional administrations need knowledge about their spatial structure and evolution. A lot of studies have mapped and analysed European cities and their evolution from optical remote sensed data but a validated and consolidated methodological framework is still missing. In this context, this research aims:

  • to study the evolution of built-up and vegetation surfaces in urban and suburban areas from HSR and VHSR images;
  • to characterize urban changes in term of urban fabrics;
  • to identify and characterize the green structure;
  • to use the existing datasets as ancillary data, and the knowledge gained in past projects to define a multiscale and replicable methodological approach that might be apply to any north-western European cities.

Project outcome

  • A multiscale methodology based on Pléiades images, HR images and ancillary data was setup to map and characterize built-up and vegetation land features in urban and suburban areas. The sole use of VHR imagery does not allow mapping the 13 classes that were foreseen with an acceptable accuracy;
  • The methodology was applied on 3 North-Western European cities with a common hierarchical scheme. Each step was described in a detailed protocol;
  • Open software (R, GRASS, OTB) and open data (Open Street Map-OSM) were used as much as possible;
  • The classification of the morphological urban area was achieved with 2 different methods relying, on the one hand on the use of OSM data for the French cities, and on the other hand on the classification of vegetated areas for Brussels. Both methods gave similar results.