A landscape potential characterization: spatial template of pedestrian ambient fields within the

urban fabric

P. Woloszyn and T. Leduc ESO and CERMA Laboratories, CNRS, France

1st  intercon+nental  Conference  of  Territorial  Intelligence    IT-Gatineau 2011, Oct. 12-14, 2011

Outline

  Context and motivations   Visual perception using isovists field   The method we developed   Use case and results   Conclusion and outlook

Powerty/inequality  measurements  

Social  Entropy  

Environmental  Entropy  

Microambients  economics  

Economical  Entropy  

Income  distribu7on  law  

Econogical  weight    

Socioecological  weight  

Socioeconomical  weight    

DEVELOPMENT  

NEEDS  

RESOURCE  

Context and motivations : the socio-ecological transition trade-off

Focus on visual ambiences : isovists field

  The isovist is simply the Gibsonian optic array, with the wavelength and intensity information omitted,

  It describes local geometrical properties of spaces with respect to individual observation points and weight all the possible view directions equally. It is a 2D horizontal slice of pedestrian's surrounding space;

  The set of all points in an environment of opaque surfaces that are visible from a given view-point;

  A useful tool to define the open space concept (= the empty space, the void, between the surrounding buildings).

Our proposal   Combine:

  A sort of “surface ray casting” strategy (an angular abscissa sampling of the star-shaped isovist),

  With a tool from information theory (Shannon entropy),   So as to produce:

  A sensory based Digital Terrain Model

Some more details

  sample the region of interest into a set of punctual positions

  in each of these punctual locations, determine the corresponding partial isovist

  convert all these isovists (2D star shaped polygons) into a set of function of radial distances (dimension reduction operation)

  let's assume that each function of radial distances represent a 1D random variable, and compute the corresponding Shannon entropy value

  represent all these entropy values into a raster color map

Function of radial distances and dimension reduction operation

  Nyquist–Shannon sampling theorem

  Shannon entropy computation

Use case

  Place Royale square

Position #1 H=0.77

Position #2 H=0.78

Position #3 H=0.86

Position #4 H=0.87

Position #5 H=0.88

Conclusion and outlook

- landscape visual space geo-topical modeling

- advanced overview of the complexity and the richness of the urban fabric

- spatial potential, allowing a pedestrian to diversify his visual landscape during his walk

Challenge is to investigate the inter-sensorial ambient-scape as a basis of a multi-sensory conception in townscape planning and design

- angular perspective variability computation

Future

Done

Acknowledgements

To: F Gonzalez Cortés (Spain) for all the developments performed on the GearScape GIS.

And to: Assistant Professor B Suner (from the National School of Architecture of Nantes city, France) for his significant help in the production of the panoramic snapshots.

References