VNIR – In the visible/near-infrared (bands 3, 2, 1), vegetation is red and green. Very “green”
vegetation, such as well watered grass, shows up as bright red. Less “green” vegetation is green
in the VNRI. Bare surfaces, such as rocks, are dark gray. Little energy is emitted from rocks at
these shorter wavelengths. Urban structures are white, while streets show up as light blue.
SWIR – In the short wave infrared (bands 8, 6, 4), vegetation is blue. Rocks and pavement are a
greenish-brown. The green tint is likely due to band 6 in the green channel, which suggest that
some component of bare rock and pavement are causing an emission. Some buildings are white.
Deposits south/southwest of South Mountain are also white. The white color likely represents
sediments, most specifically clays. Those clays are probably used in the construction of certain
rooftops. The lack of red may be due to the fact that no materials with energies that emit at those
wavelengths are in the scene.
TIR – In the thermal infrared (bands 13, 12, 10), vegetation is a teal color. The diversity in rock
composition is show in reds and blues. South Mountain is split into two hues: blue and violet.
This reflects its granitic and granodioritic composition. The Salt River is a bright pink. This
may be due to the sediment (presumably quartz rich) in the river. Sediments that showed as
white in the SWIR are pink and red in the TIR, suggesting a quartz-rich composition.
NDVI – The Normalized Difference Vegetation Index uses a combination of bands 1, 2, and 3 to
produce a single band image that displays actively photosynthesizing (e.g. healthy) vegetation.
All vegetation is white, however, brighter vegetation is healthier relative to less bright
vegetation. In the city, the lawns are gray. Along portions of the Salt River and in agricultural
settings where vegetation is likely receiving a steady supply of water and nutrients, the
vegetation is white.