Sentinel-3 LST mosaicking

Optical Toolbox
#1

Hi all!

I am trying to create a mosaic for 2 sentinel-3 level SL 2 images. I am using a tool “Mosaicking” (Raster>Geometric>Mosaicking). I am interested to get all bands mosaicked, including geometry bands, like latitude_tx, longitude_tx, sat_zenith_tn, solar_zenith_tn. However, mosaicking operator do not generate them. Do you know a way to generate those variables ?

Thanks in advance!

Best,
Paulina

#2

Mosaicing starts with a defined output image. Data from multiple input pixels that overlap a given output pixel are combined to produce a value “representative” of the output pixel. For longitude and latitude, the values are already defined by the output image. Viewing angles can vary widely amoung views of the same location on the earth’s surface, so provide no useful information for mosiac data.

#3

Thank you for your answer. I am trying to perform mosaicking of the images from the same satellite (Sentinel-3A). The images are disseminated in ‘frame’ scheme and I just need to combine them to get one image. Is there another way to do it in snap?

Thanks,
Paulina

#4

You can use the collocation tool. Which tool is best depends on what you want to do afterwards.

You can also convert all the tie-point grids into bands using BandMaths in preprocessing step.
This can be done via the command line for a batch of products with gpt or in the GUI but then it is tedious work if you have multiple products. If you do it in the GUI, ensure to uncheck the Virtual option.
I’ve mentioned this approach here: Export of conc_tsm after C2RCC processing - #2 by marpet

#5

Thanks marpet. Unfortunately collocation tool will not work here since it collocates overlapping area. in my case, I have 2 S3 land surface temperature frame images acquired on the same day and time. I would like to join them.

Thanks,
Paulina

#6

You could do that. But it’s a bit weird.
You can reproject the two product and use the Collocate with option.
Here you select the result of the mosaic. Not both results cover the same area as the mosaic
Now you can use the collocation tool or the mosaic or simply Band Maths.