Anyone have done subsetting with batch processing in SNAP successfully?


#1

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.


#2

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


#3

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?


#4

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.


#5

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.


#7

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.:sweat_smile:


#8

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.


#9

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 ?


#10

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

For DEM generation a nice demonstration was given here:

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


#11

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


#12

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


#13

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.


#14

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


#15

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


#16

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


#17

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