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i.aster.toar.1grass - Man Page

Calculates Top of Atmosphere Radiance/Reflectance/Brightness Temperature from ASTER DN.


imagery, radiometric conversion, radiance, reflectance, brightness temperature, satellite, ASTER


i.aster.toar --help
i.aster.toar [-rabcde] input=name[,name,...] dayofyear=float sun_elevation=float output=name  [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]



Output is radiance (W/m2)


VNIR is High Gain


SWIR is High Gain


VNIR is Low Gain 1


SWIR is Low Gain 1


SWIR is Low Gain 2


Allow output files to overwrite existing files


Print usage summary


Verbose module output


Quiet module output


Force launching GUI dialog


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)


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 brightness 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

in one comma-separated list.


Internally, a gain code is defined to modify gains according to spectral 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


Yann Chemin, CSU, Australia

Source Code

Available at: i.aster.toar source code (history)

Accessed: Tuesday May 14 13:41:39 2024

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