i.aster.toargrass - Online in the Cloud

PROGRAM:

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)

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 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.

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)*/

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