Search found 136 matches

by OB WebDev - norman
Thu Apr 08, 2021 3:12 pm America/New_York
Forum: All Questions/Comments
Question: MODIS 250m Processing and Composite Images
Replies: 1

Re: MODIS 250m Processing and Composite Images

Hi Amita, I have found that rhos can differ substantially from one day to the next largely because of sun angle and scan angle effects. You can get a sense of this by viewing a what are essentially rhos-based images in Worldview. Here is a comparison of the Chesapeake Bay as seen by Aqua/MODIS on Ja...
by OB WebDev - norman
Wed Feb 17, 2021 12:53 pm America/New_York
Forum: All Questions/Comments
Question: Exporting Pixel Info
Replies: 1

Exporting Pixel Info

Please start a new thread when asking a new question.

Follow the instructions here.
https://seadas.gsfc.nasa.gov/downloads/
If you run into trouble, then post (in a new thread with a descriptive subject line) specifics about the problem you are having.

Regards,
Norman
by OB WebDev - norman
Tue Jan 12, 2021 12:03 pm America/New_York
Forum: All Questions/Comments
Question: About Aqua bands
Replies: 1

About Aqua bands

Those stripes are a result of imperfect MODIS detector calibrations.  They tend to be most pronounced in areas of sun glint.  I have had success in reducing the striping by Fourier transforming the image and masking out the unwanted features in frequency space, but I am only making pretty ...
by OB WebDev - norman
Mon Nov 30, 2020 8:47 am America/New_York
Forum: All Questions/Comments
Question: MODIS AQUA Quality Flags
Replies: 8

MODIS AQUA Quality Flags

I'm not sure what you are asking here. Are you referring to these flags?

https://oceancolor.gsfc.nasa.gov/atbd/ocl2flags/

Those flag values are either on or off, making a difference computation somewhat meaningless.

Regards,
Norman
by OB WebDev - norman
Mon Nov 30, 2020 8:42 am America/New_York
Forum: All Questions/Comments
Question: MODIS AQUA SST Daytime Data
Replies: 2

MODIS AQUA SST Daytime Data

In general, you should prefer the more recently produced data.  Products are initially generated as "quicklook" files.  These are regenerated once we have received all the ancillary data needed to produce our "refined" products.  We also reprocess our data sets fro...
by OB WebDev - norman
Wed Sep 16, 2020 9:22 am America/New_York
Forum: All Questions/Comments
Question: Cloud Masking
Replies: 3

Cloud Masking

Hi Amita,I will leave it to the SeaDAS experts to answer the SeaDAS related questions.After using l2gen to generate rhos_8xx products, I usually map the data to a 16-bit imageand then use Gimp Colors->Levels... to interactively choose a threshold that separatesland and clouds from water.  The t...
by OB WebDev - norman
Fri Sep 11, 2020 11:36 am America/New_York
Forum: All Questions/Comments
Question: Data processing
Replies: 4

Data processing

You can generate a list of URLs for files to download by using our L1 browser.Specify your region and time period of interest, click "Find swaths", and then click "ORDER DATA" and follow the instructions.  You can get more information by clicking on the "Help" butt...
by OB WebDev - norman
Fri Sep 11, 2020 9:54 am America/New_York
Forum: All Questions/Comments
Question: Data processing
Replies: 4

Data processing

You have left out key portions of your script, but here is a method that works for me to download Aqua/MODIS L1 files for the month of January 2020.for f in `wget -q --post-data="sensor=aqua&sdate=2020-01-01&edate=2020-01-31&dtype=L1&results_as_file=1&addurl=1&std_only=1...
by OB WebDev - norman
Wed Aug 26, 2020 5:21 pm America/New_York
Forum: All Questions/Comments
Question: OLI L2 data
Replies: 6

OLI L2 data

Hi Amita,

There is a tool at the bottom of this page that might help you understand the l2_flags.

https://oceancolor.gsfc.nasa.gov/atbd/ocl2flags/

Try entering 2112 in the field at the bottom right.

Regards,
Norman
by OB WebDev - norman
Thu Aug 20, 2020 4:05 pm America/New_York
Forum: All Questions/Comments
Question: L2gen processing speed
Replies: 8

L2gen processing speed