Not logged inOcean Color Forum

The forum is locked.

The Ocean Color Forum has transitioned over to the Earthdata Forum (https://forum.earthdata.nasa.gov/). The information existing below will be retained for historical reference. Please sign into the Earthdata Forum for active user support.

Up Topic SeaDAS / SeaDAS - General Questions / how to remove viirs bow-tie comb-tooth (locked)
- By junzhao Date 2015-07-30 02:02
Hi,
By searching the forum, I found that the only way to remove the bow-tie lines in viirs image is mapping. I used l1mapgen to generate rgb images. Then the 'reproject' function was run using the oblique mercator method. However, the bow-tie lines still exist.
Please advice.
Your reply at your earliest convenience is greatly appreciated.
Jun
- By norman Date 2015-07-30 16:44
Hi Jun,

Could you show an example of what you mean?

Norman
- By junzhao Date 2015-08-02 09:14
Hi Norman,
What I want to do is to remove the comb-like lines in VIIRS rgb images.
Please see the image attached. I used l1mapgen to generate it. But you can see the comb-like lines on the image. Then I used the 'reproject' function in seadas to remap it in order to remove the lines.

Thanks.

Jun
Attachment: V2015151090755.png (586k)
- By seanbailey Date 2015-08-05 16:40
Jun,

l1mapgen has an "issue" with the VIIRS bow-tie deleted data.  The data are not properly flagged as invalid data, so the l1mapgen program is averaging in bad data.
A workaround until we fix l1mapgen is to do the following:

1) process the file with l2gen and output surface reflectances, e.g.:
l2gen ifile=SVM01_npp_d20150531_t0907553_e0909195_b18600_obpg_ops.h5 ofile=V2015151090755.L1A.TC.nc geofile=GMTCO_npp_d20150531_t0907553_e0909195_b18600_obpg_ops.h5 l2prod="rhos_vvv"

2) load the l2gen output file in SeaDAS and use the "Mosaic" or  "Reproject" tool to reproject the data

3) use the "View->RGB Image" tool to generate a TrueColor image.

Attached is an example output following the above steps.

Sean
- By junzhao Date 2015-08-06 06:18
Thanks for your reply, Norman.
Is it possible that the RGB image generation can be run with the GPT tool from the command line? I know that the reprojection can be done with GPT tool.
Jun
- By norman Date 2015-08-06 08:58
Um.. that was Sean who knows way more about SeaDAS than I do. :-)

Norman
- By knowles Date 2015-08-06 16:34 Edited 2015-08-07 09:57
Hi Jun

If you want to remove the comb-like lines from VIIRS images at the edges for images of land then you will have to wait.  We will soon be adding in a flag to detect these lines such that l2bin can remove these.  Over water you should be fine by using the PRODFAIL flag.

thanks
Danny
- By junzhao Date 2015-08-09 06:07
Thank you, Danny.
@Sean, any help with the command line operation to generate RGB images using the rhos products?
Jun
- By knowles Date 2015-08-10 10:06
Jun,

Sorry, but there is not currently a command line GPT operator for generating RGB images.  We plan to have this functionality in the future but no estimate on when this will be available.   L1mapgen is the only command line method at the moment for creating RGB images.

Danny
Up Topic SeaDAS / SeaDAS - General Questions / how to remove viirs bow-tie comb-tooth (locked)

Powered by mwForum 2.29.7 © 1999-2015 Markus Wichitill