Mappatura della vegetazione   Graphs of spectral signatures of water, soil and vegetation. Vegetation has a remarkably high reflection in the near infrared channel 4, and a low reflection in the visible red channel 3. This makes it possible to distinguish vegetation areas from bare ground. The difference of reflection in channels 3 and 4 is great for vegetation areas and insignificant for bare ground.   Global vegetation map for July 1992 based on a mosaic of NOAA data.   Vegetation map of Europe and Africa in July and January 1992. Bright green indicates vigorous growth and brown no growth. Compare to temperature and precipitation maps for July and January in the atlas.