Anyone have done subsetting with batch processing in SNAP successfully?

[sentinelgyb]

Anyone have done subsetting with batch processing in SNAP ? And which step should I do subset? When I am doing the SBAS, there are so many S1A products, it must be very time-consuming. So focusing on my study area may be more efficient. Thanks

Beat regards.

[ABraun]

I had good experiences with this graph:

Read > Apply Orbit File > Subset

You can create an WKT of your subset area here and use it in the graph builder (choose geographic coordinates)
https://arthur-e.github.io/Wicket/sandbox-gmaps3.html

[sentinelgyb]

Thanks for your response, ABraun. Can subset operator be applied to the original Sentinel-1A IW SLC product downloaded from ESA before I conduct PS/SBAS?

[sentinelgyb]

I have tried subset the original Sentinel-1A IW SLC products, but it throwed an error said as following.

What should I do to accomplish this subset step?

Looking forward to hearing from you. Thanks.

[ABraun]

Delete the second Read operator. Generally, only select one input for your graph. Then use the graph on multiple products in batch mode.
Graph files are always for processing one dataset at a time. The batch mode allows you to load multiple data and one graph which si applied to all of them.

[sentinelgyb]

I have deleted one Read operator, and tried again. Same error occurred as above mentioned.

Moreover, The source Bands is empty. I am confused why this subset can not be done.

[ABraun]

I now see that you are using a SLC product. If you work with SLC data, you can create subsets using the TOPS Split Operator to select only a sub-swath and a few bursts.
Demonstrated here: The Order of DEM Creating Steps

You can even use the TOPS Coregistration to create subsets of coregistered image pairs.

[sentinelgyb]

Thanks, ABraun. I have applied subset operator to Tops Coregistration resulting image. But when I tried to apply Tops Deburst operator to the Interferogram Formation subseting result, an error occurred as follows.

I wonder which step should the subseting be applied If I want to generate a DEM or Displacement ?

[ABraun]

subset after debursting. Otherwise the operator doesn’t get the correct geometries.

For DEM generation a nice demonstration was given here:

The Order of DEM Creating Steps

I am trying to create a DEM over my AOI. After reading plenty of topics, I have obtained a pair of S1A and S1B data. The baseline is 143.48 which is the longest I could find. As I read, it should be between 150 and 300 and around 70% of the values in the coherence histogram should be above 0.4. This is the histogram of my recent and best attempt. [image] After applying the steps below; 1) S1 TOPS Coregistration 2) Creating Interferogram 3) Debursting 4) Goldenstein Phase Filtering 5) Mu…

For displacement detection topographic phase removal must be applied on the interferogram (preferably after debursting and subsetting)

[Prakash]

Dear Sir,
My AOI is in IW2, and I tries to make subset to avoid java heap space, I try to make at the step of coregistration too, by decreasing the area.
So before making subset every SLC product need to resample ?,
I try it, but no data for IW2 or IW3, after resampling.
Would you suggest me any idea to cope with this problem?

Sincerely
Prakash

[ABraun]

Why doyou want to resample at all? Just select the swath (IW2) and burst to reduce the area.

[Prakash]

Dear Sir
I came back quite late.
I am trying to make displacement map of a particular area and following are the result of the process.
Please help me and suggest me to get the good result.
Sincerely
Prakash
coregistration of two image

for coregistration other parameter are selected as per tutorial for tops sar interferometry. I tries more combination but result is not much different.

you can notice my process, where only default has benn used and VV band has been selected from initial.

I do the filter two times and send snaphu export and import

snaphu import

and after displacement map
reasuklt is

after phase unwarping, we can clearly noticed that the reasult has some error, because there is a big area having same displacement.
the source data are just before and after the heavy rainfall with some big landslide reasulting landslide dam too.
The result is not clear.
Please help me with this.

[ABraun]

have a look at your coherence image. This gives you a clue where your results are reliable (coherence > 0.4)

[Prakash]

Dear Sir
Thank you very much for your comment. My result is not good on the low coherence area. I was considering the process also. Is there any way to increase the coherence or solve this problem.
Is it ok to say that sentaline 1 A and B images are not good for low coherence area, for measuring displacement?
PolSAR may be good for low coherence images.

Sincerely
Prakash

[ABraun]

regarding low coherence, please have a look at these explanations:

Some explanations about concepts of fringes of interferogram and coherence

Atmospheric phase cannot be removed by a SNAP module as it cannot be modeled, like flat earth phase or topographic phase, for example. If you would make reference measurements of water vapor or have dense time-series data (example) you could theoretically remove the atmospherical phase distortions. This is advanced however (example 2). You calculate an interferogram between a pair of images. It shows you the differences between both images regarding their single phase signal. As the satellite…

[shiva]

I am Shiva , I am trying to process the SAR Data using snap. actually my work area in IW 1 and IW 2 , where i don’t need IW 3 . actually I use SLC data as project is study land subsidence. Is there any way to merge both IW 1 and IW 2 so that i can process the data to get more details. thanks and waiting for your reply

[Shadi1]

@ABraun

Delete the second Read operator. Generally, only select one input for your graph. Then use the graph on multiple products in batch mode.

There are multiple products, each of which contains multiple bands. I would like to extract only the coherence bands from each product. The subset operator even after putting it on a graph will only work with one product individually because the band selected for the subset is identified by its file name. therefore, the subset graph will only work on one product during Batch processing, which is the product that was selected during creating the graph. Or am I doing something wrong?