Is Google Earth Engine Sentinel-1 GRD product Sigma0?

Microwave Toolbox
#1

Hi,

I wanted to know if the Sentinel-1 GRD pre-processed product available on Google Earth Engine Sigma0, Beta0 or Gamma0.

  • Are all 3 forms available under the GEE platform?

  • If not, how do we convert from one form to another?

Thanks

#2

why not ask to the GEE support (follow from here)?

This is a SNAP forum, a place to for obtaining community help for a specific ESA software - not Google… even specific Sentinel information is better request from the official channels..

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#3

GRD data in EE are sigma nought. You can convert to gamma nought as described in this thread (eg, see this script).

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#4

Thanks @simonf, this helped!

#5

Yes the data is in SigmaNaught dB.
Read the google earth documentation here in the “Pre-Processing” Section.

The data on EE is Orbit & Terrain Corrected, Border and Thermal Noise Suppressed already in SNAP before ingesting to EE servers. However lets say you are doing speckle filter or some other task where sigmaNaught dB is not required. You have to have the data in Linear Form, Rather than going back from dB to linear you can directly call the linear data(image collection) inside GEE.
COPERNICUS/S1_GRD_FLOAT

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#6

Same Image In Linear Form

Screen Shot 2021-06-15 at 4.42.07 AM
Screen Shot 2021-06-15 at 4.42.07 AM1237Ă—604 244 KB

Same In SigmaNaught dB

Screen Shot 2021-06-15 at 4.42.34 AM
Screen Shot 2021-06-15 at 4.42.34 AM1240Ă—622 258 KB

I hope this helps :wink: and feel free to ask GEE related questions.

#7

Hello, how can I get the sigmanaugh DB value of a specific location in a long period of time on GEE? Where do I need to find the relevant code? I learned from Gee’s sentinel-1 algorithm that the pixel value obtained from GEE is the Sigma value I need (if I understand correctly :sweat_smile:). I look forward to your reply~

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#8

Watch my video on it

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#9

To extract time-series pixel values in earth engine watch this video, I assume you’re talking about time-series, if you are having trouble with reducers feel free to ask here

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#10

@ABraun Hi,
Please move this thread to polarimetry section as interferometry is not available on GEE. The hashtags it has contains interferometry.

And if possible please make a new category of “Google Earth Engine” because data of ESA Sentinels is there S1 GRD, S2 MSI L1C & 2A, Sentinel 5.

Time-series data is available on just one click.

We will have our dedicated portion :grin::slightly_smiling_face:

#11

actually, the #s1tbx subforum is neither dedicated to interferometry nor polarimetry, both are separate areas. So it fits well here I’d say.

We will not create a separate subforum for the Google Earth Engine, there is already an official board for this and we want to concentrate the contents of this forum on SNAP. Until now, we tolerated topics dealing with other software, and we are happy that this forum is visited by so many people, but we don’t want to create an official space for exchance for external tools or services .

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#12

But the data diversity & number of people I would hope the board decides for other platforms too. After all it’s all under the umbrella of Copernicus program. Nonetheless!

#13

Step forum is way more organized and open to public. Easily accessible on even a google search.

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#14

Hello, thank you for your reply. I’ve spent too much time on the road these days. I’ll watch the video you shared carefully~

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#15

Hi, my dear friend, I’ve watched a series of videos you shared over and over again. I’d like to say that these videos have benefited me a lot. Thank you very much for your sharing and best regards. :kissing_heart:

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#16

All the best :slightly_smiling_face:

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#17

Can you share the steps that are required specifically to go from sigma to beta values of Sentinel-1 GRD products

#18

Hi,
Similarly is there any way to convert the sigma0 data in GEE to beta0?

Thanks