## 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

i.landsat.toar, r.in.aster

ASTER sensor data download: ASTER: Advanced Spaceborne Thermal Emission and Reflection Radiometer

## AUTHOR

Yann Chemin, CSU, Australia