Coherence Estimation

I’m using SLC product of Sentinel-1 for coherence estimation but while doing back geocoding i lost one band of SLC please guide me about this problem.

please make sure you have installed all updates (Help > Check for Updates) and use SRTM 1Sec in the BackGeocoding step because SRTM 3Sec was reported to cause some problems lately.

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SRTM 1Sec also not working.
Updates start downloading but gone down with message.


These updates are required to update. do we have any other way to update them manually?


try any other DEM with AutoDownload. If none of them works, SNAP has problems accessing online resources from your computer.

simply click Next, the rest is done automatically.

Yes none on AutoDownload is not working so how can solve out this problem?

I click next but downloading 30-40% it shows error server unavailable.

both indicates that the host server ist currently not available. You simply have to wait some time until it is ready again.

Also make sure that none of your security settings or firewalls is preventing SNAP from accessing online sources. This has been reported to cause downloading errors a couple of times.

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All updates are done. I applied almost every autoDownload DEM but still a band is blank.

where is your data located?

Its located in C drive

sorry, I meant your study area.

Lahore, Pakistan.

this is inside the area covered by SRTM, so we can exclude that as an error. You can manually download the SRTM data and use it as an external DEM.

This seems similar to the the problem I brought up a while ago.
I still have not overcome the issue. Actually, recent attempts make me wonder, if it has not got worse.
For me, one back-geocoded band got lost if S1A was a master, but S1B was a slave (always the same subswath, same burst from different slices), I started processing this spring data (only S1A yet) and I already got an empty band for that burst and not always (e.g. data from four dates D1, D2, D3, D4, coherence of D2 and D3 was bad, other two were ok).

I downloaded SRTM 1sec from earth explorer and used it as a external DEM but still a blank band is there.

yes problem is same but have you find any solution to it?

can you please share the product name of the two scenes you are using and which steps you applied?


These Products are currently I’m using