NAME
i.aster.toar - Calculates Top of Atmosphere Radiance/Reflectance/Brightness Temperature from ASTER DN.
KEYWORDS
imagery,
radiometric conversion,
Terra-ASTER,
radiance,
reflectance,
brightness temperature
SYNOPSIS
i.aster.toar
i.aster.toar --help
i.aster.toar [-rabcde] input=name[,name,...] dayofyear=float sun_elevation=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)
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 after importing your Aster imagery from storage format 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.
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)*/
i.landsat.toar,
r.in.aster
Yann Chemin, CSU, Australia
Last changed: $Date: 2014-12-09 18:31:29 +0100 (Tue, 09 Dec 2014) $
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GRASS Development Team,
GRASS GIS 7.0.3 Reference Manual