Dear Ben, To perform SBAS processing on a subset of the area of your data stack, you would want to first create the subset stack using the tool found under SARscape > Interferometric Stacking > Stacking Tools > Sample Selection SAR Geometry Data. This will coregister the data stack and then extract the subset area from each dataset in the stack. The results will be appropriate to use as input to the SBAS process. Regards, Peg

Hi Peg, Thanks for the clarification. I will attempt to use that tool instead. On another note, I noticed that the FTP address for SRTM - Version 4 (xftp.jrc.it) and Sentinel-1 hub (https://scihub.esa.int/dhus) is no longer valid. I believe S1 data hub is now https://scihub.copernicus.eu/dhus. I manually changed it in the FTP address portion, but the download will not run. Is there anything else apart from the base_url that I have to update? Also, is there a new link for the SRTM Version 4 DEM download? Else, how can I do it manually? Thank you Regards Ben

I have tried using SAR sample selection in stacking tools. However, upon inspecting the _pwr images, the area of interest differs. This leads me to think that the images were not coregistered. Is there any parameter I should be looking out for in order to coregister the images? I'm working on S1-A SLC imagery.

Hi Ben, I should have mentioned this earlier. Once you have started the Sample Selection SAR Geometry Data tool, you will select the input files. Then you will want to go to the Parameters tab, and under the Principal Parameters make sure that you set Make Coregistration to True. The default value there is False. Under that tab, you can also specify map coordinates or image coordinates for your subset, if you aren't passing in a vector file to define your subset. Note that you can also click on the Principal Paramaters button to show a drop down list of other parameters you might want to change. In particular, if you are entering your subset coordinates as slant range coordinates (either via a vector file or by entering image coordinates based on an SLC file), you will want to identify here a multilooked power image corresponding to an SLC input file. Best, Peg

Dear Peg Oh I see, that makes sense now. For creation of the vector shapefile, I assume I'm supposed to do it on a _pwr image? Then, for the input files, the _slc_list file corresponding to this _pwr image (and vector) should be at the top (first) of the inputs. The reference image should then be this _pwr image. For srtm i realise the jrc server is now obsolete. cgiar server has to be used. Also, how can I update the new copernicus sentinel1 path in sarscape? Thank you Regards Ben

Also, when importing Sentinel-1 data, how can I apply precise orbits? I have set the two folders: AUX_POEORB and AUX_RESORB with the precise orbit files. Restituted orbits are empty (only using precise). During importing, I do not receive any notification that precise orbits have been applied. How do I check if orbits are now precise? Regards Ben

Hi Ben, In the latest version of SARscape, you will find a tool for updating Sentinel data to precise orbits, under SARscape > General Tools > Orbital Correction > Update to Precise Orbits. - Peg

Hi Ben, You have control over where SARscape looks for Sentinel data by starting up the tool under SARscape > Import Data > Sentinel Download. Then go to the Parameters tab and you will see the the parameters base_url and data_url etc which you can change. The base URL in the current version of SARscape is https://scihub.copernicus.eu/dhus/, which I believe is still good. You can create the vector shapefile on any image that you wish. If you make it on an image that is in slant range, though, you need to account for that by providing an image that has information about how that image is oriented. SARscape can then use that to figure out how to convert those vector coordinates to the right locations in all of the datsets in the stack. - Peg

I see, but it seems that the tool only allows updating of one file each time right? is there a faster way to do this for a large number of acquisitions? During import, if I enter the precise orbit files manually in the optional orbit files dialog, will the precise orbits be used in the sentinel 1 import? I have also read that setting the orbit folder in the preferences directory will allow sarscape to automatically use the orbit files. I have created such folder and have set the directory accordingly, however I'm not sure if the SLC files are updated based on the precise orbits.

Just wondering, I am currently running SBAS interferometric process step. there is a step called "...Cut image...sentinel1" it seems to get stuck or is taking very long time. Is this normal?

I realised that under the Other Parameters in the interferometric processing, range looks was default at -2. Not sure why this was so. I changed the value to 5 and the process seems to go on. What should the no. of range looks for Sentinel 1 be?