ASTER User's Guide - Aster - NASA

ASTER Users Handbook
The L1B data product is generated, by default, in UTM projection in swath orientation, and
Cubic Convolution resampling. An L1B in a different projection and/or resampling method can
be produced on request from GDS in Japan (Table 2).
Table 2: Resampling Methods and Projections Available for Producing Level-1B
products.
Resampling methods Map Projections
Nearest Neighbor (NN) Geographic (EQRECT)
Cubic Convolution (CC) Lambert Conformal Conic (LAMCC)
Bi-Linear (BL) Space Oblique Mercator (SOM)
Polar Stereographic (PS)
Universal Transverse Mercator (UTM)
Each image contains geolocation information stored as a series of arrays. There is one set of
geolocation information (array) per nadir telescope (3 sets total). Each geolocation array is 11 x
11 elements size, with the top left element (0,0) in the image for the nadir views. For the
backward view the image is offset with respect to the geolocation array. The nadir VNIR and
backward-viewing VNIR images use the same latitude/longitude array, except the backwardviewing
image is offset with respect to the nadir image.
The L1B latitude and longitude geolocation arrays are two 11 x 11 matrices of geocentric
latitude and geodetic longitude in units of degrees. The block size of the geolocation array is 420
lines by 498 samples for the VNIR bands; 210 lines by 249 samples for the SWIR bands; and 70
lines by 83 samples for the TIR bands.
Appendix I provides a dump of the metadata contained in a L1B data product. There are five
metadata groups:
Productmetadata.0
Productmetadata.1
Productmetadata.V
Productmetadata.S
Productmetadata.T
…………….
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