Sentinel-1A with SNAP


1. Install SNAP

          Choose All Toolboxes ~ Windows 64-bit (check your system)

               In SNAP, Tools ~ Options ~ Performance ~ Compute


2. Download Sentinel-1A Data

    2.1. For seamless download, use FireFox web browser ( )

    2.2. Download Sentinel-1A Data

        a. Sign up and login to

        b. Choose a rectangular area

        c. Product Type : Choose SLC (single look complex )for InSAR

        d. Sensor Mode: IW (Interferometric Wide swath - default mode for S-1A)

        e. Search and Download (2~3 hours per scene if lucky)

        f. Check data with SNAP: 

                    (File ~ ) Open Products : select a *.zip file

                    Double click (Product Explorer ~ Bands ~) Intensity_IW1_HH, etc. to check data.

                    Run (Radar ~ Sentinel 1 TOPS  ~ )  S-1 SLC to GRD  to check data.


3. Sentinel-1A TOPS Interferometry

    TOPS Interferometry Tutorial

    a. (File ~ ) Open Products :  Select two *.zip files for InSAR

    b. (Radar ~ Coregistration ~) S-1 TOPS Coregistration : (5~7 minutes for each IW)

        - Choose two images in Read and Read(2) respectively.

        - Select IW1 for TOPS-Split and TOPS-Split(2).

        - Use GETASSE30 for Back geocoding of Antarctic Area (Use SRTM for scenes with latitude from S60 to N60).

        - Add '_IW1' to the output name

        - Run and check

        - Repeat for IW2 and IW3.

    c. (Radar ~ Interferometirc ~ Products ~ ) Interferogram Formation : (25~30 minutes for each IW)

        - Run for IW1, IW2, and IW3 separately.

    d. (Radar ~ Sentinel-1 TOPS ~ ) S-1 TOPS Deburst : (20 ~ 40 minutes for each IW)

        - Run for IW1, IW2, and IW3 separately.

        - Try several times or skip if error occurs.

    e. (Radar ~ Interferometric ~ Products ~ ) Topographic Phase Removal: (15 ~ 20 minutes for each IW)

        - It is available only after Deburst.

        - Use GETASSE30 DEM for Antarctic Area (Use SRTM for scenes with latitude from S60 to N60).

        - Run for IW1, IW2, and IW3 separately.

    f. (Radar ~ Interferometric ~ Filtering ~ ) Goldstein Phase Filtering: (20 ~ 25 minutes for each IW)

         - Run for IW1, IW2, and IW3 separately.

    g. (Radar ~ Geometric ~ Terrain Correction ~ ) Range-Doppler Terrain Correction: (20 ~ 30 minutes)

         - Select all source bands with Ctrl +.

         - Run for IW1, IW2, and IW3 separately.

    h. Right click the phase image and select "Spatial subset from view"

        - Adjust Scene Step X, Y to reduce the file size down to 20 MB (or even 10 MB depending on the computer resources).

         - Run for IW1, IW2, and IW3 separately.

    i. Right click the image and select "Export image to KMZ"

         - Run for IW1, IW2, and IW3 separately.

    j. Double click KMZ and see the image in Google Earth.


    (Option 1.) (Radar ~ Sentinel-1 TOPS ~ ) S-1 TOPS Merge

        - IW1, IW2, and IW3 can be merged in any steps after (d.) Deburst and before (g.) Range-Doppler Terrain Correction

        - I recommend to merge after (f.) Goldstein Filtering.

        - Add '_IW123' to the output file name.

    (Option 2.) (Raster ~ Geometric ~ ) Reprojection

        - It occurs error if "S-1 TOPS Merge" is not used previously.

        - It can substitute Range-Doppler Terrain Correction.

        - Use WGS84 datum for KMZ output.

        - Check "Fit to size" and adjust "Pixel Resolution" by 10 x 10 to reduce the output file size.

        - Check "Reset" at Output Parameters to set the center coordinates.

    (Note 1) Graph Builder doesn't work on my machine. Maybe


4. SNAPHU with Windows VMWare

    ( Reference:  Sentinel-1 Stripmap Interferometry)

    a. Download and Install VMWare Workstation 12.1.1 Player for Windows 64-bit operating systems. (

    b. Download  ubuntu-16.04.1-desktop-amd64

    c. In VMWare,

        - memory > 8GB (16GB recommended)

        - Harddisk ~ 500GB


        - Options ~ Shared folders: always enable, ubuntu_data, D:\ubuntu_data


        - Create OS using ubuntu iso image (it takes for a while)

        - Player ~ Manage ~ Reinstall VMWare Tools -> move *.tar.gz file into Desktop (or Home) -> Search and open Terminal

        - In Terminal,

            > cd Desktop

            > gunzip -c *.tar.gz | tar -xvf -

            > sudo ./

            (Press Enter several times to the end.)

            Check if /mnt/hgfs/ubunto_data is created.


    d. Download and install SNAPHU

        In Terminal,

        > sudo apt-get install snaphu

        > snaphu


    e. Export to SNAPHU

        - Save the wrapped interferogram into the shared folder: SNAP ~ Radar ~ Interferometric ~ Unwrapping ~ Snaphu Export

        - Statistical-cost mode: Select TOPO for topography, DEFO for deformation.

        - Run (Subset the image if it takes forever! Save the subset product to avoid error in data format.)



    f. Run SNAPHU

        - In Linux Terminal, open snaphu.conf file with more command

            > more snaphu.conf

        - Copy the command (left mouse dragging), paste it to the command line (middle mouse click) and run (enter).

            > q (to quit more)

            > snaphu -f snaphu.conf Phase_ifg_srd__06Aug2015_18Aug2015.snaphu.img 64700

            - If it takes forever, subset the image.

    g. Import the unwrapped interferogram into SNAP.

                SNAP ~ Radar ~ Interferometric ~ Unwrapping ~ Snaphu Import

    h. Change from unwrapped phase to displacement

                SNAP ~ Radar ~ Interferometric ~ Products ~ Phase to Displacement




    a. SNAP ~ Raster ~ Band Maths....