[ESIP-all] LP DAAC Release of the ASTER Precision Terrain Corrected Product

Lemig, Kelly klemig at usgs.gov
Wed May 6 14:08:38 EDT 2015

In March 2015, the Land Processes Distributed Active Archive Center (LP
DAAC) began processing the Advanced Spaceborne Thermal Emission and
Reflection Radiometer (ASTER) Level 1 Precision Terrain Corrected
Registered At-sensor Radiance (AST_L1T) product.  The new AST_L1T product
provides quick turn-around of consistent GIS-ready data as a multi-file
product, which includes a HDF-EOS data file, full-resolution composite
images (FRI) as GeoTIFFs for tasked sensors (e.g. VNIR/SWIR and TIR), and
associated metadata files.  In addition, each AST_L1T granule contains
related products including low-resolution browse, and when applicable, a QA
browse and QA text report.

NASA LP DAAC has created the AST_L1T product by applying modified Landsat
geometric algorithms to ASTER Level 1 data. The AST_L1T algorithm applies
Earth and satellite models, control points, and elevation models,
ultimately projecting the result onto a rotated north-up map at full
instrument resolution.

 AST_L1T features a single resampling from the AST_L1A for use in
investigations, or in the future, as input into Level 2 Earth surface
parameter generation, such as surface reflectance and temperature

AST_L1T granule names are constructed as L1T Short Name (e.g. AST_L1T),
Collection Version (e.g. 003), Start Date-Time-Group (e.g. mmddyyyyhhmmss),
Production Date-Time-Group (e.g. mmddyyhhmmss), and Processing Random
Number (e.g. 12345).

Each scene contains multiple files.  Please refer to the table below for
file extension interpretation.
 *File type* *Extension Code for file* Science data file .hdf Metadata
.hdf.met FRI VNIR/SWIR bands *(GeoTIFF)* _V.tiff FRI for TIR bands
*(GeoTIFF)* _T.tiff Browse bundled in a single HDF file _BR.hdf Line,
sample locations of the control points that correlated and comprehensive
set of information regarding the verification _QA.txt Individual browse
files* .jpg

*The individual browse files may end in _BR_#.jpg where the # may be  2, 3,
or 4. What these numbers represent depends on how many browse jpeg files
are included in the scene/granule.  If there are three browse, then 2 =
VNIR/SWIR, 3 = TIR, and 4 = QA.  Alternately, if only two browse are
available, then 2 = VNIR/SWIR or TIR depending on the sensors acquired and
3 = TIR or QA. Then if only 1 browse is available it may be VNIR/SWIR or
TIR depending on sensors acquired.

The AST_L1T data are available over the United States and territories at no
charge to all users. In addition, approved NASA supported researchers and
their affiliates, educational users, and federal partners may order AST_L1T
from the LP DAAC global collection.  To become approved for global access,
users must first register by creating a NASA account to search and order,
then complete and submit an application form available online at

For further information, please refer to the AST_L1T Product page
<https://lpdaac.usgs.gov/products/aster_products_table/ast_l1t>, or
contact User
Services <lpdaac at usgs.gov>.  Additional supporting documentation such as
the AST_L1T ATBD, User Guide, and Product Specification will be released as
they become available.
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