Earthdata Forum

I'm trying to geolocate VIIRS, and I'm getting:

WARNING - Using NPP defaults for CMNGEO_PLATFORM_LUT
scan: 0 of 203
Unable to open directory (/optics1/software/seadas/seadas-7.5/ocssw/share/viirs/dem/) for reading DEM files.

So I went looking for DEM-LWM.tar.gz (ftp://samoa.gsfc.nasa.gov/pub/VIIRSL1/) to put it in my $OCDATAROOT/viirsn directory.
https://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?pid=28055#pid28055
There is no longer access to a ftp server, and the getfile script fails as well. Were can I find the Digital Elevation Map (DEM) data set now?

wget https://oceandata.sci.gsfc.nasa.gov/cgi/getfile/DEM-LWM.tar.gz
--2018-05-11 11:25:12--  https://oceandata.sci.gsfc.nasa.gov/cgi/getfile/DEM-LWM.tar.gz           
Resolving oceandata.sci.gsfc.nasa.gov... xx.xxx.xx.xx, 2001:4d0:2418:128::84                    
Connecting to oceandata.sci.gsfc.nasa.gov|xx.xxx.xx.xx|:443... connected.                       
HTTP request sent, awaiting response... 404 Not Found

yes, we had to get rid of our FTP server :cry:

I put the VIIRS DEM files on our data server, so you can grab them.  The file is 1.1GB:

https://oceandata.sci.gsfc.nasa.gov/ocssw/dem.tar.gz

The default place to install it is here:

$ cd $OCSSWROOT/share/viirs
$ tar xzf dem.tar.gz

don

Dear Don

I'm trying to process a viirs image from L1A to L2, however, it is getting white gaps at the image. In the calibrate_viirs step I'm getting:

WARNING - Using NPP defaults for CMNGEO_PLATFORM_LUT

I've grabbed the DEM file and pasted it to seadas-7.5.1/ocssw/share/viirs and I am still getting the same problem.
I have a masOC High Sierra v10.13.6
Please, could you guide me to install de DEM file in the right way and fix those white gaps?

Thank you, I really appreciate that.

Best,

Amália

I am assuming that the white gaps you are talking about are horizontal lines on the outer edges of the image.  They are the bowtie deleted pixels which are deleted before the data is sent from the spacecraft.  The warning you are getting is not a problem.  Here is one discussion:

https://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?pid=29784;hl=viirs%20bowtie

This is another explanation.  You need to hover your mouse over the A,B,... boxes to see which pixels are deleted.

https://oceancolor.gsfc.nasa.gov/docs/bowtie/viirs/

don

Dear Don

Thank you very much for your assistance and help.

I am sorry, maybe I did not express well, those white gaps are actually strips across the entire image and not just the border (outer edges).
Is there something that I could improve it during the processing? Or are those strips because of the "bowtie effect"?

Best,

Amália

The bowtie deletion of the VIIRS data makes stripes on the outer third on both sides.  The middle third should not have any stripes.  The deleted pixels are flagged as BOWTIEDEL in the L2 file, so ignore those pixels when doing calculations.  If you want a nice picture, you will need to map the data.

don

Dear Don

Thanks for your help!
How can I map the data in the L2 file VIIRS images?

Amália