700 
Figure 1 : Map of the 10xl0km2 study area. 
The thick lines indicate the flight axis used 
during the measurements. The dashed line 
indicates a typical POLDER field of view 
when the instrument is located at the vertical 
of the point shown with a cross. The Rhone 
river and two canals are also shown. 
10 km 
Figure 2 : Typical directional reflectance 
diagram for a sunflower field at 550 ran (top) 
and 850 nm (bottom). The black circle 
represents the average zenith angle of the 
Sun, on the <i> = 0° axis. See text for 
indications. 
10 km