Relief inversion effect in terrain represen-tations: Where should we place the light source?

Julien Biland, Dr. Arzu Coltekin ISPRS Geospatial Week 2015, 1 October 2015

?

Julien Biland & Arzu Coltekin

The  red  dots  appear  to  lie  on..?  

Quickbird image Xinjiang, China

Ridge

Julien Biland & Arzu Coltekin

And  image  upside  down  

Quickbird image Xinjiang, China

Ridge

Julien Biland & Arzu Coltekin

The  red  dots  appear  to  lie  on..?  

Ikonos image Mt Richmond, New Zealand

Ridge

Julien Biland & Arzu Coltekin

And  image  upside  down  

Ikonos image Mt Richmond, New Zealand

Ridge

Julien Biland & Arzu Coltekin

Contradic8ons?  

Quickbird image Chagang, North Korea

Valley

Julien Biland & Arzu Coltekin

Contradic8ons?  

§  Geo-knowledge can hint that your perception is wrong §  and maybe it overrides your initial shape perception

§  Shape perception dependent on:

§  Familiarity §  Assumption of light position §  Convexity-bias

Julien Biland & Arzu Coltekin

How  to  judge  true  landform  shape  in  SRM?  

Ridge

The  red  dots  appear  to  lie  on..?  

Caucasus

Julien Biland & Arzu Coltekin

Land  cover  helps  

Quickbird image Caucasus

Ridge

Julien Biland & Arzu Coltekin

Influence  of  light  direc8on  

Julien Biland & Arzu Coltekin

§  Illumination position very crucial §  Which direction is best? §  Come see our poster P33 to find out

Conclusion  

Julien Biland & Arzu Coltekin

Thank  you  for  your  aEen8on!  

Valley in Russia Ikonos image