1 October 2003
Figure 5-30. ASTER (SWIR) image of a copper
mine site in Nevada. Red/pink = kaolinite, green =
Courtesy of NASA/GSFC/METI/ERSDAC/JAROS,
and U.S./Japan ASTER Science Team.
(d) Water (Water, Clouds, Snow, and Ice). As previously mentioned, the
clear water peaks in the blue region of the spectrum. A ratio of band 5/band 2 is
to 1.75-mm range distinguishes clouds, ice, and snow. See Figure 5-32.
(e) Urban Settings. Objects in an urban setting include man-made fea-
tures, such as buildings, roads, and parks. The variations in the materials and size
of the structure will greatly affect the spectral data in an urban scene. These fea-
tures are well depicted in the visible range of the spectrum. Near infrared is also
useful in distinguishing urban park areas. Urban development is well defined in
false-color and true color aerial photographs, and in high resolution hyperspectral
data. The thermal infrared range (10.5 to 11.5 m) is another useful range owing
to the high emittance of energy. A principal components analysis may aid in
highlighting particular urban features. See Figure 5-33.