SLC to GRD processing?

Can you guide me how to do it step by step?, please!
I want to work in urban area

I can’t do that, sorry.
It is basically calibrating and co-registering SLC images and then looking for changes. But it requires a bit of willingness to learn new things from your side.

I have collected a few documents which help you to acces the world of SAR in another post. The topic initially dealt with interferometry and crop monitoring but the same applies to change detection.

Good luck!

Thank you so much!:slight_smile:

I do this step to preprocess my SLC data and convert to GRD for change detection in urban area without any decrease in resolution on 2 images with exactly 1 year in between
Does anyone think it is true?
1- at first I use S-1 TOPS split to reduce amount of computation and select area of interest
2- Apply orbit file
3- Radiometric > calibrate (here I don’t know in processing parameter select either save as complex output or output sigma0 beta0 gamma0. because when I select complex output in further step SNAP says it shouldn’t be complex)
4- S-1 Thermal noise removal
5- S-1 TOPS deburst
6- Geometric> Slant range to ground range
7- make a graph that includes just { read> GRD-post> write }
is it appropriate after this step I do :
SAR application > urban area> speckle divergence
Radiometric> radiometric terrain flattening
Geometric > terrain correction> Range doppler terrain correction
how about Ellipsoid correction

I am so thankful if every one can help me

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Is the workflow correct for GRD data processing? I attended an ESA workshop last year and we were asked to perform multilooking on GRD data (ftp://ftp.itc.nl/pub/dragon4/SAR/D1SP1-S1TBXIntro-MFoumelis/Dragon_2017_D1SP1_Cookbook_SNAP.pdf)

image

Also, does this process also account for the topographic variations in the data or do I need to perform some other step (such as terrain flattening) for that? If yes, then my final product will be gamma not (instead of sigma not). So is it ok to perform the analysis with gamma values?

Which order should ThermalNoiseReduction and Calibration be run and if it makes any difference then what are the difference(s)?

Earlier in this thread (see above) lveci’s graph shows Cal>TNR but SLC to GRD within SNAP runs them the other way round.

Thank you

It should not make any difference in the results. That being said, sometimes users find a new creative ordering of the operators that triggers errors in some cases. Therefore we are defining a set of “recommended processing graphs” to simplify finding a working solution.

When you say “we are defining …” I guess that implies you are in the process of doing this - unless you are referring to the SLC to GRD graph that already exists within the Radar tools menu.

But if a set of “recommended processing graphs” exists elsewhere or will do in the near future please point me towards them.

Many thanks for the very prompt reply!

story of my life

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Dear Andy I’d like to comeback to this point, Applying speckel divergence on GRD, Do you have any suggestions on the following approach?

Thermal noise removal--------->apply orbit --------->calibration to sigma0--------->apply speckel divergence,

The other question is, which window do you suggest in urban approach in speckel divergence?

I don’t have experience in tuning this operator, sorry. I would systematically increase and reduce it to see which window size is most suitable for your case.

Hello. I will very appreciated if somebody helps. How from GDR make SLC or how with GDR from S1A make coregistration and interforogram or how from .h5 CosmoSkymed make interferogram. I often have an errors in difrent stages. Can anybody prompt me clear algoritms with such files.

you can turn SLC into GRD products but not in reverse.