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Last Post 07 Jul 2016 11:31 AM by  Enrique Blondel
Aster L1T data Convert to Emissivity
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Enrique Blondel



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07 Jul 2016 11:31 AM
    Good day Mari and/or Peg, I am trying to convert Aster L1T TIR data to Emissivity and temperature, from L1B is pretty straightforward but so far I am not getting consistent results from L1T data as DN values are very different compared to L1B data. Also in regards to Aster L1T SWIR data what are the preprocessing steps to follow? Please provide help. Many thanks Enrique

    Mari Minari



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    07 Jul 2016 12:45 PM
    Hello Enrique, The main difference with ASTER L1B and L1T is that the scale factors are *not* automatically applied to ASTER L1T so the data are still in byte values. You can use the Radiometric Calibration tool to convert the SWIR and TIR bands to TOA radiance (and for SWIR you can also calculate TOA reflectance). Once the TIR bands are in the expected radiance units of W/m^2*sr*um then you can input this data to the Emissivity tools that are available. What do you want to do with the SWIR bands? With the Radiometric Calibration tool, you can calculate radiance or TOA reflectance. If you plan on applying an Atmospheric correction with FLAASH/Quac, you would want to calibrate to radiance and then use FLAASH/Quac to calculate surface reflectance. I typically would stack the VNIR-SWIR radiance bands into a single cube (resampling to the VNIR pixel size) prior to applying the atmospheric correction. - mari

    Enrique Blondel



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    07 Jul 2016 12:53 PM
    Hello Mari, many thanks for your kind and prompt reply, best regards Enrique
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