Geoscience Reference
In-Depth Information
a
b
c
d
Fig. 8.2
Despeckled section of the blue band of a Landsat image covering the Chew Bahir
catchment in Southern Ethiopia;
a
original image, b despeckled image, c surface plots of the
original image, and d surface plot of the image at er despeckling. Original image courtesy of
the Landsat Program of the US National Aeronautics and Space Administration (NASA) and
the US Geological Survey (USGS).
8.5 Importing and Georeferencing TERRA ASTER Images
In Section 8.3 we used a processed ASTER image that we downloaded from
the ASTER webpage. In this section we will use raw data from this sensor.
h e ASTER sensor is mounted on the TERRA satellite launched in 1999,
part of the Earth Observing System (EOS) series of multi-national NASA
satellites (Abrams and Hook 2002). ASTER stands for
Advanced Spaceborne
h ermal Emission and Rel ection Radiometer
, providing high-resolution (15
to 90 meter) images of the earth in 14 bands, including three visible to near
infrared bands (VNIR bands 1 to 3), six short-wave infrared bands (SWIR
bands 4 to 9), and i ve thermal (or long-wave) infrared bands (TIR bands 10
to 14). ASTER images are used to map the surface temperature, emissivity,
and rel ectance of the earth's surface. h e 3rd near infrared band is recorded
twice: once with the sensor pointing directly downwards (band 3N, where
