AST_07XT VNIR Band Order and Wavelengths

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sedatinal79
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Joined: Mon Oct 05, 2020 5:33 pm America/New_York

AST_07XT VNIR Band Order and Wavelengths

by sedatinal79 » Mon Oct 05, 2020 5:50 pm America/New_York

Hi, first of all thanks for the data sharing with public. Recently i ordered and download ASTER scene ( AST_07XT_00305192005082601_20201001075438_21295.hdf and *.hdf.met files) for my phd thesis. I order this AST_07XT data level because of don't want to apply any atmospheric or cross talk correction to AST_L1T data set.
But when i import the data to Excelis ENVI, band order and wavelengths are listed below;

ASTER VNIR Band1: 0.6610
ASTER VNIR Band2: 0.8070
ASTER VNIR Band3N: 0.8040

Should these order and wavelengths be listed below?

VNIR_Band 1 VNIR Band 1 (0.52 to 0.60 µm)
VNIR_Band2 VNIR Band 2 (0.63 to 0.69 µm)
VNIR_Band3N VNIR Band 3 (0.78 to 0.86 µm)

So where is the VNIR Band1 (0.52-0.60)or(0.5560) ?

Could you please tell me this if there is something i missed?
Attachments
ENVI software (5.3) band view
ENVI software (5.3) band view
image (1).png (98.45 KiB) Not viewed yet

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LP DAAC - jwilson
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Re: AST_07XT VNIR Band Order and Wavelengths

by LP DAAC - jwilson » Tue Oct 06, 2020 12:30 pm America/New_York

Greetings,
Thank you for sending us your Earthdata forum question.
We are forwarding your inquiry to our subject matter expert for further guidance.
Thank you,
Janice

sedatinal79
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Joined: Mon Oct 05, 2020 5:33 pm America/New_York

Re: AST_07XT VNIR Band Order and Wavelengths

by sedatinal79 » Tue Oct 06, 2020 12:59 pm America/New_York

I'm waiting impatiently, Janice.

LP DAAC - jwilson
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Re: AST_07XT VNIR Band Order and Wavelengths

by LP DAAC - jwilson » Wed Oct 07, 2020 4:23 pm America/New_York

Our subject matter expert tested a couple of granules and they didn't see what the user saw. The spectral coverage from bands 1 - 3 from my end are inline with ASTER data. We will download the data ordered.

It would be helpful to know which atmospheric correction profiles he used when he requested the data and how he uploaded the image via ENVI?

Kind regards,
Janice

sedatinal79
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Joined: Mon Oct 05, 2020 5:33 pm America/New_York

Re: AST_07XT VNIR Band Order and Wavelengths

by sedatinal79 » Thu Oct 08, 2020 2:31 am America/New_York

At 5th Oct. 20, i also order and download 3 other granules;

AST_07XT_00307112001083437_20201005143144_16978.hdf
AST_07XT_00309052004082553_20201005143114_16779.hdf
AST_07XT_00309162002082802_20201005143114_16777.hdf

have same foot prints with the granule in my first post. Ok, both these and the one first, looks like inline with ASTER but they display in band wiew wrong wavelengths associated with the bands (figure: AST_07XT VNIR band view in ENVI).

Let's see how i upload the granules to ENVI Classic 5.3 with IDL; File > Open Externel Files > EOS > ASTER as the original *.hdf file ordered and dowloaded granule from earth data search web site without any preprocessing like atmospheric or geometric corrections. Because i choose this L2 Surface reflectance data set for ready to use before any corrections like atmospheric and crosstalk etc.

Maybe, figure: a spectral profile view of any pixel in one of these granules helps you to understand my problem about wavelengths.

Also i can display another ASTER L1T product inline with ASTER with right wavelengths same way in ENVI (figure: ASTER L1T band view in ENVI)
Attachments
AST_07XT VNIR band view in ENVI
AST_07XT VNIR band view in ENVI
3.jpg (105.19 KiB) Not viewed yet
a spectral profile view of any pixel in one of these granules
a spectral profile view of any pixel in one of these granules
2.jpg (38.31 KiB) Not viewed yet
ASTER L1T band view in ENVI
ASTER L1T band view in ENVI
4.jpg (106.42 KiB) Not viewed yet
Last edited by sedatinal79 on Thu Oct 08, 2020 3:31 am America/New_York, edited 1 time in total.

LP DAAC - jwilson
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Re: AST_07XT VNIR Band Order and Wavelengths

by LP DAAC - jwilson » Fri Oct 09, 2020 9:09 am America/New_York

Please find the reply from our ASTER data specialist who downloaded the data ordered from Oct 5, 2020...keep in mind we do not endorse software.

I tried to duplicate the problem in ENVI classic 5.5 as well as the new version and I didn't see any of the issues the user encountered. It might be his setting or preference.

The user should contact Harris Help Desk and inquire about the issue with ENVI not displaying band information correctly.

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