JPSS VIIRS EDR data processing for one band

[Margad]

Hello everyone,
I want to use JPSS VIIRS EDR data from NOAA,
Is it possible to process by Python on Windows using Polar2grid?
How to convert from .h5 to GeoTiff?

Thank you

[kathys]

Hello,

Polar2Grid is not supported on Windows Operating Systems. However, we have tested parts of Polar2Grid Version 3.0 on Windows Subsystem for Linux (WSL) Ubuntu. As the documentation says "Windows Subsystem for Linux (WSL) is a feature of Windows that allows you to run a Linux environment on your Windows machine, without the need for a separate virtual machine or dual booting."

You can learn more about it here: https://learn.microsoft.com/en-us/windows/wsl/about

Good luck,

Kathy

[Margad]

Thank you for your answer. I will attempt to use a virtual machine.
I downloaded the data 'GIGTO-VI1BO-VI2BO_j02_d20230827_t0619596_e0626029_b04114_c20231212153222550898_oebc_ops.h5' from NOAA Class. Is it possible to process this data using polar2Grid? Only SDR is available?

Thank you
Regards,
Margad

Hello,

Polar2Grid is not supported on Windows Operating Systems. However, we have tested parts of Polar2Grid Version 3.0 on Windows Subsystem for Linux (WSL) Ubuntu. As the documentation says "Windows Subsystem for Linux (WSL) is a feature of Windows that allows you to run a Linux environment on your Windows machine, without the need for a separate virtual machine or dual booting."

You can learn more about it here: https://learn.microsoft.com/en-us/windows/wsl/about

Good luck,

Kathy

[kathys]

Hello,

The data that you downloaded from NOAA CLASS is not SDR data, it is the NOAA Imagery EDR. Polar2Grid does not support that product.

The CLASS menu option to choose is "JPSS VIIRS SDR Operational (VIIRS_SDR).

If you choose "De-aggregate JPSS Data Products" under the CLASS "User Preferences" options from the links along the left side of the website, then you will get individual granules, and not the combined geolocation/data aggregates. Once you have these individual data and geolocation granules, then you can use Polar2Grid to create images.

Good luck,

Kathy

[Margad]

Hello,

Thank you for your helpful reply, I have two additional questions:
1. The resolution of the I-band is 375 meters. If I want to remap an image by i-band resolution, should I create my own grid?
2. How to create a true_color image by i-band?

Thank you,
Margad

[kathys]

Hello Margad,

1.) To create a 375 m spatial resolution image, you will need to create your own grid. The easiest way to do this is by using the p2g_grid_helper.sh script. You can find instructions on how to use this script in the Polar2Grid documentation, online at : https://www.ssec.wisc.edu/software/pola ... ripts.html

2). To create a 375m true color image, you need to first create a grid definition file, as described in 1). above, and then execute the polar2grid.sh script and providing the path and name of your new grid file and grid name to the software. For example:

polar2grid.sh -r viirs_sdr -w geotiff -p true_color --grid-configs /home/p2g/my_grids.yaml -g my_grid_name -f <path to input VIIRS SDR files>

Good luck,

Kathy

[Margad]

Dear Kathy

I have a couple more questions regarding our recent discussions:
1. Could you please advise on the process of obtaining Surface Reflectance (Bottom of Atmosphere reflectance) from SDR data?
2. I'm also curious about whether Polar2grid exclusively produces Top of Atmosphere (TOA) radiance, or if it also provides information on TOA reflectance.

Thank you,

Regards Margad

[kathys]

Hello again Margad,

> 1. Could you please advise on the process of obtaining Surface Reflectance (Bottom of Atmosphere reflectance) from SDR data?
The SDRs do not contain surface reflectances. They contain observed radiances at the satellite sensor above the atmosphere, which are then also converted to reflectances or brightness temperatures. NOAA has a Surface Reflectance product which is available to either order from NOAA CLASS, or AWS. The CSPP software also supports the creation of Surface Reflectances for direct broadcast users. You can learn more about it here:

https://cimss.ssec.wisc.edu/cspp/viirs_lsr_v1.1.shtml

> 2. I'm also curious about whether Polar2grid exclusively produces Top of Atmosphere (TOA) radiance, or if it also provides information on TOA reflectance.
Polar2Grid is a tool that allows you to create images. It is not science software. So if you create images from SDRs, it will be Top of Atmopshere radiances, reflectances or brightness temperatures, depending on what options you choose.

I hope this helps,

Kathy

[Margad]

Hello Kathy

Thanks for your help last time – it was super useful!

I'm currently aiming to obtain VIIRS BOA Surface Reflectance data. How about .nc surface reflectance files into simple image files (.tif)?
Also, can Polar2grid handle those .nc files?

Thanks a bunch for your ongoing support!

Regards,
Margad

[kathys]

Hello Margad,

There are programs that can read and write data files and save them as different formats. For example, the gdal command gdal_tranlsate can do this. You can find this and other utilities at https://gdal.org.

The next release of Polar2Grid (Version 3.1) will support VIIRS Land Surface Reflectance NetCDF output products. We plan to release this in the next 6 weeks.

Good luck,

Kathy