Best Option for backgeocoding in Alaska

Dear all,

I would like to study the earthquake in Alaska using InSAR and SNAP processing but I found that there is no SRTM DEM in that area. I chose the ASTER DEM option for backgeocoding step in Coregistration processing. When I saw the produced interferogram, I found it in the same color means there is a fault in my selection. So, could you please guide me about this issue?

Best regards,

I think Aster GDEM is covered Alaska,

[quote=“SMJ.Mirzadeh, post:1, topic:15162”]

What do you mean?

Would you please to share the result!

Or , I think, it is possible to create the DEM yourself, and use it as an external DEM.

Thank you so much. I need to run again to check the results. Based on your suggestion, should I choose this option?

But this option is not based on auto download. Is it a problem?

That’s mean you need to download it yourself, from here,


Oh no. I need to select auto options. Which one do you suggest me to select?

Unfortunately, as I mentioned in previous post , you should download it yourself, because it couldn’t be auto-downloaded,

Concerning the auto option, if the DEM covers your AOI, then would be fine to select it, but in your case SRTM doesn’t cover your AOI.

I can find and download it simple using but I don’t know about the suitable format for SNAP because after downloading, I should mosaic them. Could you please tell me which format is suitable? Envi standard or Geotiff?

Thank you so much

Yes this also good option to download it.

I’d recommend Geotiff, DEM must be WGS84,

Have a look at this post please,

Thank you so much for your great information. In your view, AW3D DEM can be a good case as External DEM in SNAP? and also, I should give the SNAP software the DEM as same size as whole of S1 image or only my study area?

It is interesting to see your result in testing both since AW3D DEM, is very high resolution, in my personal opinion too high resolution DEM doesn’t affect the result, since the resolution of S1 is much higher.

AW3D DEM has an as same spatial resolution (30m) as the SRTM 1 sec but it is a little difficult to download the external DEM for the whole of S1 image.

I was thinking you meant this AW3D DEM,

Wooooo, so great DEM. I didn’t know about it. Do you know how can I access it? Is it free or need to pay

Excuse me, the GETASSE30 (Auto Download) also works now?! Because, I saw the another post so that the guys said this option global and good enough for TOPS-coregistration.

You could check it up in here,

In case coves your AOI, why not, go ahead,