Handle Sentinel-1 RTC product

[jaimebayes]

Hi there,

I am trying to process an RTC (Radiometric Terrein Corrected) image, but it was not recognized, generates a warning that avoid next lines to execute.

Code s1_path = "S1B_IW_20211113T231329_DVP_RTC10_G_gdufed_8DC5.zip" s1_prod = reader.open(s1_path)

Output WARNING:eoreader:There is no existing products in EOReader corresponding to S1B_IW_20211113T231329_DVP_RTC10_G_gdufed_8DC5.zip

Environment:

• Python version: Python 3.10.12
• sertit-utils version: `import eoreader; Python 3.10.12

Additional context Colab

[remi-braun]

Hello,

Your Sentinel-1 product seems not to be in SAFE format. Indeed, its name is odd.

The warning is here to prevent you that EOReader doesn't recognize your S1 product.

Could you confirm its format is ad-hoc ?

Edit: I didn't knew what RTC is, but it's for sure not an ESA format, is it ? If not EOReader doesn't handle them, sadly 😅 See what SAR product type EOReader handles here: https://eoreader.readthedocs.io/en/latest/sar.html#product-type-handling

[LabSR-UT]

Hi,

That is the name Vertex ASF portal (https://search.asf.alaska.edu) assign after applying RTC to a SAFE image.

Hope it helps,

[remi-braun]

Yes OK that's what I read.

Is there a real community need to handle those unofficial products ?

[remi-braun]

@jaimebayes @LabSR-UT Could you please tell me how to download these products ? I need samples for implementation. Are they available outside USA ?

[LabSR-UT]

Sure, I download them through the vertex ASF web portal. First, I select what image of interest, then before downloading I submit it as a job (see image below) to obtain an RTC (Radiometric Terrain Corrected) image, which usually takes some days to be ready to download. I do this because if I download the image without RTC, it does not overlap correctly with other datasets.

Hope this helps,

[image: image.png]

[remi-braun]

Ok so this is an additional product, you have to ask for. I was looking on the portal without seeing a way to download a RTC product.

So, you never orthorectify GRD data on your own ?

[LabSR-UT]

Right, it is an additional product. I never have orthorectified GRD data before, because I do not have a high resolution DEM to do that. Although, I consider orthorectify would not fix that wide displacement, but I never tried it, by the way. Is there a way using the EOreader to apply orthorectification to Sentinel-1 imagery? It would be great to know how to do it.

[remi-braun]

Yes EOReader will orthorectify your data by default if you give it a SAFE file. The default DEM is the same than the one used by ASF (COPDEM GLO-30). You can pass other DEMs if you want.

The only requirement is that you install ESA SNAP on your computer and have its tool gpt in your path.

Some ressources that might help you:

• https://eoreader.readthedocs.io/en/v0.20.4/sar.html
• https://eoreader.readthedocs.io/en/v0.20.4/notebooks/SAR.html
• https://eoreader.readthedocs.io/en/v0.20.4/faq.html#snap
• https://eoreader.readthedocs.io/en/v0.20.4/faq.html#sar-data-fails-to-load-extent
• https://eoreader.readthedocs.io/en/v0.20.4/faq.html#snap-dem-vs-other-dem

[LabSR-UT]

Great, I will give it a try. Thanks for the resources and help. I hope to use this platform deeper, I am just a newbie on it.

Best regards,

[remi-braun]

Feel free to ask for help if needed 😉

[LabSR-UT]

Thanks, I will!

[remi-braun]

ASF Sentinel-1 RTC products are now handled by EOReader. You can clone the 0.21.0 branch to try it up :)

[remi-braun]

0.21.0 is up today :)

[jaimebayes]

Hi Dr. Remi,

Thanks, I am trying it with RTC and it works really fine (see image below). Thanks for sharing the new version. I want to know all its functions and uses.

Best regards,

[image: image.png]

On Mon, Jan 8, 2024 at 3:15 AM Rémi Braun @.***> wrote:

0.21.0 is up today :)

— Reply to this email directly, view it on GitHub https://github.com/sertit/eoreader/issues/112#issuecomment-1880544460, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABCENPNC2NF4GBLRL2O6W3TYNOTI5AVCNFSM6AAAAAA6PRSIS2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQOBQGU2DINBWGA . You are receiving this because you were mentioned.Message ID: @.***>

--

Jaime Lopez Carvajal

[remi-braun]

Sadly I don't see the image 😅

[LabSR-UT]

Sorry, I attached the image here.

[LabSR-UT]

Here, the RTC clip plot