i.aster.toar(1grass) GRASS GIS User's Manual i.aster.toar(1grass)
NAME
i.aster.toar - Calculates Top of Atmosphere Radiance/Re-
flectance/Brightness Temperature from ASTER DN.
KEYWORDS
imagery, radiometric conversion, radiance, reflectance, brightness tem-
perature, satellite, ASTER
SYNOPSIS
i.aster.toar
i.aster.toar --help
i.aster.toar [-rabcde] input=name[,name,...] dayofyear=float sun_eleva-
tion=float output=name [--overwrite] [--help] [--verbose] [--quiet]
[--ui]
Flags:
-r
Output is radiance (W/m2)
-a
VNIR is High Gain
-b
SWIR is High Gain
-c
VNIR is Low Gain 1
-d
SWIR is Low Gain 1
-e
SWIR is Low Gain 2
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
input=name[,name,...] [required]
Names of ASTER DN layers (15 layers)
dayofyear=float [required]
Day of Year of satellite overpass [0-366]
sun_elevation=float [required]
Sun elevation angle (degrees, < 90.0)
output=name [required]
Base name of the output layers (will add .x)
DESCRIPTION
i.aster.toar calculates the Top Of Atmosphere (TOA) reflectance for
Terra-ASTER L1B in the visible, NIR and SWIR bands (9+1 bands) and
brigthness temperature for the TIR bands (5 bands), all from L1B DN
values. It is useful to apply after import of original ASTER imagery
that is generally in standard DN values range.
The order of input bands is
• VNIR: 1,2,3N,3B
• SWIR: 4,5,6,7,8,9
• TIR: 10,11,12,13,14
in one comma-separated list.
NOTES
Internally, a gain code is defined to modify gains according to spec-
tral bands following the GeoSystems GmbH ATCOR Ver. 2.0 Calibration
Files. The function is defined in gain_aster.c file.
/*Gain Code*/
/*0 - High (Not Applicable for band 10-14: TIR)*/
/*1 - Normal*/
/*2 - Low 1(Not Applicable for band 10-14: TIR)*/
/*3 - Low 2(Not Applicable for Band 1-3N/B and 10-14)*/
SEE ALSO
i.landsat.toar, r.in.aster
ASTER sensor data download: ASTER: Advanced Spaceborne Thermal Emission
and Reflection Radiometer
AUTHOR
Yann Chemin, CSU, Australia
SOURCE CODE
Available at: i.aster.toar source code (history)
Accessed: unknown
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GRASS 7.8.7 i.aster.toar(1grass)
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