Search found 1449 matches

by OB.DAAC - SeanBailey
Fri Jul 28, 2017 3:42 pm America/New_York
Forum: Questions/Comments
Question: Atmospheric correction for NIR-Red bands of MODIS
Replies: 4

Atmospheric correction for NIR-Red bands of MODIS

The source data are available from our L1/2 browser.  For MODIS, you would need to process the L1A data to produce an L1B and geolocation file to input into l2gen for processing.   SeaDAS is the software of choice :grin:  However, we do not yet support data processing under the W...
by OB.DAAC - SeanBailey
Thu Jul 27, 2017 6:57 pm America/New_York
Forum: Questions/Comments
Question: l2gen resolution 250 m
Replies: 6

l2gen resolution 250 m

Cassandra,

The resolution is only a nominal resolution at nadir.  Off nadir, the pixels will grow.  For example, a 1km nominal pixel is more like 2x5 km at the edge of the swath.

Sean
by OB.DAAC - SeanBailey
Thu Jul 27, 2017 8:27 am America/New_York
Forum: Questions/Comments
Question: Atmospheric correction for NIR-Red bands of MODIS
Replies: 4

Atmospheric correction for NIR-Red bands of MODIS

Mohd,The bands *are* atmospherically corrected.The default atmospheric correction approach uses the NIR bands (748 and 869nm for MODIS), and so we do not report Rrs for the bands used in the aerosol determination in our standard products.  However, you can process the data to return the Rrs val...
by OB.DAAC - SeanBailey
Thu Jul 27, 2017 7:47 am America/New_York
Forum: Questions/Comments
Question: l2gen resolution 250 m
Replies: 6

l2gen resolution 250 m

Casandra, The 1km resolution bands will not magically obtain a higher resolution when processed at 250m.  The only bands that will truly be at 250m are the 645 and 859nm bands.The others will interpolated (but effectively be supersampled) to 250m resolution and will appear blockier than the nat...
by OB.DAAC - SeanBailey
Thu Jul 27, 2017 7:27 am America/New_York
Forum: Questions/Comments
Question: L1B problems
Replies: 14

L1B problems

You can use the Band Properties option to set the spectral wavelength for the bands manually (right click on the band in the File Manager tab to select the Properties GUI).
Once you have set the wavelengths, the Spectrum View GUI will identify the data as capable of being displayed.

Regards,
Sean
by OB.DAAC - SeanBailey
Tue Jul 25, 2017 8:36 pm America/New_York
Forum: Questions/Comments
Question: L1B problems
Replies: 14

L1B problems

Correct, the L1B data do not include geolocation information.  For that you will need to generate the geolocation file, which SeaDAS is set up to do.  This is the same as it is for MODIS.  While the L1B for MODIS does include a subsampled geolocation data set, SeaDAS does not use it a...
by OB.DAAC - SeanBailey
Tue Jul 25, 2017 8:31 pm America/New_York
Forum: Questions/Comments
Question: My subscriptions are empty
Replies: 7

My subscriptions are empty

Jacques,If you're subscription was indeed successfully entered (ignoring what the script may report) it would show up when you look at your subscription list.As a test, I created a new, non-extracted subscription - and for me it worked.I looked at your account and I do not see a new subscription...
by OB.DAAC - SeanBailey
Tue Jul 25, 2017 7:18 am America/New_York
Forum: Questions/Comments
Question: L1B problems
Replies: 14

L1B problems

The VIIRS L1A product we distribute contains the full sensor suite of bands.  SeaDAS is distributed with code to process the L1A to L1B (calibrate_viirs) and can output the IMG(375m), MOD(750m) and DNB (day/night panchromatic band) data, as well as the geolocation file (geolocate_viirs).  ...
by OB.DAAC - SeanBailey
Mon Jul 24, 2017 11:08 am America/New_York
Forum: Questions/Comments
Question: L1B problems
Replies: 14

L1B problems

Use the NASA VIIRS L1A product distributed but the OB.DAAC.  The SeaDAS processing code includes support for this version of VIIRS data, but not the SDR data distributed by MODAPS.

Sean
by OB.DAAC - SeanBailey
Mon Jul 24, 2017 10:49 am America/New_York
Forum: Questions/Comments
Question: My subscriptions are empty
Replies: 7

My subscriptions are empty

Jacques,There are two forms of data subscription both served by the same order form.  The default is for an extracted/mapped data subscription.You have to select at least one of the product types in the top section (NetCDF/HDF Data Files) of the subscription form to get non-extracted subscripti...