| 13 Jan 2009 09:21 AM |
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We have recently purchased from USGS through a local reseller a couple of ASTER images Level 1A collected in 2008.
These images were delivered as zip files containing, per band, files as below :
AST_L1A_00305012008092831_20081219160421_4187.VNIR_Supplement.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Supplement_Temp.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Supplement_Encoder.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Supplement_Chopper.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.SightVector.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.SatelliteVelocity.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.SatellitePosition.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.RadiometricCorrTable.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.ObservationTime.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.Longitude.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.LatticePoint.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.Latitude.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.IntertelescopeOffset.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.ImageData.tif
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.AttitudeRate.txt
AST_L1A_00305012008092831_20081219160421_4187.TIR_Band14.AttitudeAngle.txt
The tiff/geotif file is a non georefernced one. Of course it is profound that among these files neither HDF file format exists nor any file containing obvious (to us or immediately imported by ENVI) RPC information in order to perform orthorectification and DEM extraction.
Has anyone worked with such aster files before. Any idea how to build RPCs or create an ENVI header file.
Kind Regards,
Alex
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MariM
Veteran Member
Posts:2396  
| 14 Jan 2009 01:24 PM |
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I believe the USGS always delivers ASTER in HDF format but I could be wrong. It looks to me your reseller opened the HDF files and saved all the data and metadata information into separate files. This is unfortunate. It is the HDF and ENVI's ability to parse the HDF for ASTER that allows ENVI to calculate RPCs from the sensor information (they do not come in the file) and perform the orthorectification. I would try to request the original HDF files if possible since ENVI will recognize them as ASTER and open them with the appropriate metadata, and also apply the calibration factors. I cannot tell, but it also looks like you only received 1 band of data (TIR band 14)? That would be unusual for 1A data which will contain the VNIR, SWIR and TIR bands.
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Deleted User
New Member
Posts: 
| 14 Jan 2009 03:33 PM |
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Thank you fpr posting.
These were delivered by USGS, we cant tell why tey were not in an hdf format, since it is not the first time we order and use aster data.
The listing of the filenames is only for band 14. There was no point in listing all of the filenames. All banfds were included in the zip file.
We have already reorder the data set in hdf format..
Kind regards,
Alex
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MariM
Veteran Member
Posts:2396
| 15 Jan 2009 08:27 AM |
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Perhaps they also output to TIFF so that some users can look at the data in a simple image processing package that can read TIFF and not something as complex as HDF. However, if you really want to orthorectify this data in ENVI, it will be necessary to have access to the original HDF. Good luck!
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