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Topic: DAT vs HDF

ERSDAC, which now is the primary commercial point of sale for level L1A ASTER imagery, delivers data in a .DAT whereas COSI-Corr requires .HDF for the ancillary file. Any suggestions how solve this problem?

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Re: DAT vs HDF

Really? For some reason we're still receiving the data in .hdf format, but I don't think we're ordering them via ERSDAC. Can you specify the format when you place your order? It doesn't make sense for them to go back to the old CEOS format, which have never been used by the ASTER community before. I suppose NASA was doing the hdf encapsulation?
Anyway, would you have some metadata you could send us so we could have a look?

Thanks,
Sebastien

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Re: DAT vs HDF

It seems that you can still obtain ASTER images in .hdf format via ERSDAC:
http://www.gds.aster.ersdac.or.jp/gds_w … q.c_e.html

Sebastien

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Re: DAT vs HDF

I ordered two files. One had all radiometers (VNIR, SWIR, TIR), the other contained only VNIR. By simply changing the extension of the first file from .DAT to .HDF, I managed to let COSI-Corr read the ancillary information of the first file, but that trick didn't work for the second file. COSI-Corr choked. In the future, I guess I'll have to make sure that all wavelengths are included in the file.

Pieter

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Re: DAT vs HDF

Hi Pieter,

Well, they should normally deliver you with .hdf data in any case. I find it very weird because the CEOS format has been obsolete for a long time and they actually specify on their website that the default format is .hdf. Maybe you could contact their customer service? There's no reason you should have to change the filename either.

Sebastien

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Re: DAT vs HDF

Sebastien,

You can actually choose between CEOS or HDF. My confusion stemmed from the fact that the HDF files produced by ERSDAC, for some reason, have a .DAT file extension. Other than that, the file contents appear to be the same as for those produced by WIST (but only if you order all wavelengths). This was confirmed by the ERSDAC customer service.

Pieter

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Re: DAT vs HDF

Hi Pieter,

The SWIR instrument stopped working recently. So what happens for the recent images, which are delivered without the SWIR bands? is the HDF format modified?

Thanks,
Sebastien

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Re: DAT vs HDF

I don't know what happens for recent images. My VNIR-only file was from 2000. I have since re-ordered the same scene with all instruments and that solved the problem. I will let you know what happens with recent images next time I order one.

Salut,

Pieter