Dear SNAP developers and users,
I am a new user of SNAP, I tried to process Sentinel-1 data, the first step is radiometric-calibration, after this I wanted to do geometric correction, I used Geometric-ellipsoid correction-average height range-doppler, but error occurred, the error message is
Is there anyone know what’s the problem? It would be appreciated if someone could help me out on this.
Dear SNAP developers and users,
first of all, let me welcome you as a new SNAP user.
If you have a question, it’s good when you open a dedicated thread for it. I did this for you.
The error message is hardly readable in the image. Can you attach it in a higher resolution?
I see it says that the product can’t be written. can you check the path and if you have write permission?
Thanks for your reply. The error message is :
A problem occurred during processing the target product processing.
Message: Not able to write product file “C:\Users\mfh278\Downloads\calibration data\S1B_EW_GRDM_1SSH_20170516T110027_20170516T110132_005622_009D90_52A4_Cal_EC”
even if I changed the path, the same error happened.
What output format did you select?
I chose BEAM-DIMAP.
I can do other correction, such as stereographic_south_pole, WGS84. but I can not do polar stereographic.
I’m not sure but maybe the EW mode is not compatible with polar stereographic projections. Where is your data located?
my data is located in the antarctic. Somebody hasd used sarscape to get it .
what happens when you use WGS84 as an output? Maybe you can re-project afterwards.
I am processing the Sentinel-1 GRD data with the following workflow:
- Apply orbit file
- Multi temporal filtering
- Terrain correction
- Radiometric calibration and backscatter normalization
- Linear to dB
However SNAP gives an error that calibration cannot be applied to the coregistered product.
This is the recommended workflow from
Nelson, A., Setiyono, T., Rala, A. B., Quicho, E. D., Raviz, J. V., Abonete, P. J., … & Thongbai, P. (2014). Towards an operational SAR-based rice monitoring system in Asia: Examples from 13 demonstration sites across Asia in the RIICE project. Remote Sensing , 6 (11), 10773-10812.
Can someone please comment on this.
Radiometric calibration should take place before co-registration while backscatter normalisation can stay where it is now. This is the order SNAP supports. The end-result will be the same.
Thanks for your comment.
Is the SAR processing workflow different for different sensors? Eg. Radarsat-2 dual pol from Sentinel-1
How come this document from ESA states a different order of steps for SAR processing (slide 53)?
The order of steps depends on the software used to process the images. If the processing-chain is correctly implemented the end result should be identical for practical purposes.
Is there any scientific reasoning behind why calibration can’t be applied to a co-registered output?
No, it is how S1TBX/SNAP software is designed. It is not possible to cover and test every imaginable order of the processing steps that the graph-processing allows, and therefore some steps need to be performed before some other steps. Like I said earlier the order does not affect the quality of the end result that will be identical for all practical purposes. You should care about the end-result, not in what order some steps were computed.