i.aster.toar
Calculates Top of Atmosphere Radiance/Reflectance/Brightness Temperature from ASTER DN.
i.aster.toar [-rabcde] input=name [,name,...] dayofyear=float sun_elevation=float output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]
Example:
i.aster.toar input=name dayofyear=float sun_elevation=float output=name
grass.script.run_command("i.aster.toar", input, dayofyear, sun_elevation, output, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("i.aster.toar", input="name", dayofyear=float, sun_elevation=float, output="name")
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)
-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
--qq
Very quiet module output
--ui
Force launching GUI dialog
input : str | list[str], required
Names of ASTER DN layers (15 layers)
Used as: input, raster, name
dayofyear : float, required
Day of Year of satellite overpass [0-366]
sun_elevation : float, required
Sun elevation angle (degrees, < 90.0)
output : str, required
Base name of the output layers (will add .x)
Used as: output, raster, name
flags : str, optional
Allowed values: r, a, b, c, d, e
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: bool, optional
Allow output files to overwrite existing files
Default: False
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
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 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
- 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 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
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)
Latest change: Wednesday Apr 02 17:48:37 2025 in commit 571253a