Hi Frederico, I also have problems with the external dems in the s1- toolbox. Earlier in NEST the dem had to be in wgs84, the geoid had to be substrated, the format had to be tiff the height in meters. Then it sometimes worked, I think the pixel depth was important. What is your error message?

Hi Christoph, the error message is without reference (see attached file)

Oh that's not really a helpfull mesaage... Maybe the old NEST Forum helps:

I found this post::

https://earth.esa.int/web/nest/user-community/forum/-/message_boards/message/1645241?_19_redirect=https%3A%2F%2Fearth.esa.int%2Fweb%2Fnest%2Fuser-community%2Fforum%2F-%2Fmessage_boards%2Fsearch%3F_19_keywords%3Dexternal%26_19_searchCategoryId%3D0%26_19_breadcrumbsCategoryId%3D0%26_19_redirect%3Dhttps%253A%252F%252Fearth.esa.int%252Fweb%252Fnest%252Fuser-community%252Fforum%253Fp_p_id%253D19%2526p_p_lifecycle%253D0%2526p_p_state%253Dnormal%2526p_p_mode%253Dview%2526p_p_col_id%253Dcolumn-5%2526p_p_col_count%253D1%26_19_formDate%3D1433331930229

Unfortunately I cannot find a good user forum for the s1-toolbox...

Any progress on this issue? 

I have the following error message while using a geotiff dem (WGS84)... 

A problem occurred during the target product initialisation.

Type: OperatorException

Message: Operator 'RangeDopplerGeocodingOp': Value for 'Digital Elevation Model' is invalid: 'External DEM'

There seems to be a lot of development going on, they even have a new forum with this issue already opened:

http://forum.step.esa.int/t/how-might-i-use-the-external-dems-in-sentinel-1-toolbox/84

BTW: The s1Toolbox will be included to the SNAP, based on the STEP Platform... they are really good in making new names for their tools...

How can I use external DEM in SNAP coregistration instead of SRTM and others? I tried with .asc, but SNAP shows java.lang.NullPointerException error. Any ideas?

The solution is to uncheck the re-grid method. Unfortunately in SNAP 6 the option is removed, but if you display the parameters, you see it is set to TRUE.

There are more solutions:

1) create a graph and export it as an XML, then edit it in an editor and set false or

2) ditch SNAP 6, install SNAP 5 and uncheck it in the GUI.

Hope they will solve this in the next release.

Error opening the zip file everytime I try to apply terrain correction. What is the possible solution?