Bands in Sentinel 1 Level 1 (GRD, RAW and SLC) products - basic information

you are the scientist :wink:

If you want to use the rasters from SNAP in a GIS you can simply open the .img files in the data folder of the BEAM-DIMAP format. I suggest this because conversion to GeoTiff has some negative aspects:

  • increased file size
  • basically a duplicate of the img file
  • unnecessary processing time
  • loss of metadata information
  • conversion issues regarding data type (compression, range of values…)

I am not scientist, just s/w engineering!!!
Anyway, we developed many analysis with IDL s/w read the geotiff format.
We do not have GIS.

alright :slight_smile:

Just be aware of the mentioned error sources, especially the data type.

I have zone question,
If product is between 2 zones, which zone you will use for
creating the xml using gpt command line? where exactly the parameters to define the zone from GRD or SLC products?

you define the UTM zone in the projection step, usually in Range Doppler Terrain correction.
Generally you take the zone with the larger coverage in your scene.

Yes that is work perfect.
I build the xml not using the snap. where I get information to get zone?

I would first build a graph in SNAP then export it as an XML. Then you see how the parameters are compoed.

Do all the processing in BEAM-DIMAP and export to Geotiff in a separate step only after the processing is done. Not doing this can cause strange problems.

How to processing data eliminate the bad data on the both side/top/bottom?
I did by using subset, but that is manual, I would like to automate.

Hi !
Out of all the available bands (real (i) and imaginary (q) parts and a virtual intensity) and subswaths(IW1,IW2,IW3) in level-1 SLC which one should i use for calibration in SNAP for getting backscatter data and can you tell step by step process for getting backscatter data .

Please have a look here:

Hello ABraun,

been reading that post, can you please specify on opening the .img file of the BEAM-DIMAP folder? Where is this .img file located? I see various .hdr files etc, but no .img.


depending on your Windows configuration, the extension *.img is not shown. It is the file without any extension then. But to go sure you can display all file extensions with this option:


Hello ABraun,
Thanks for replying. I will elaborate on my question: On an answer above, in this thread, you mentioned that instead of exporting a raster in GeoTIFF in order to open it in a GIS, one can simply open the .img file of the BEAM-DIMAP folder. (I assume the BEAM-DIMAP folder is inside the .SAFE folder) The file types I see in the .SAFE folder of an S-1 product are: XML, PDF, SAFE, XSD, PNG, KML, HTML, TIFF. So this is my question: Which is the file you are referring to in the post (the .img) , because I would like to try importing it into a GIS, so far I export GeoTIFFs and want to see if your proposed method is more efficient.
Thank you in advance,

now I understand. Before you open Sentinel-1 data in any GIS you need to pre-process it. It is neither calibrated nor projected in the .SAFE format and cannot be used right away. For GRD products, the minimum steps are listed here: Radiometric & Geometric Correction Workflow

Once you processed your data, it will be written in a BEAM DIMAP format. This is how SNAP handles the raster and metadata of the product. It consists of a *.dim file and a *.data folder. In the data folder, there are hdr files and img files and the latter can be opened in QGIS. But you need to terrain corrected data for that.

This makes sense. Will have a look at it. Thanks for the input :slight_smile:

Is possible to express the real (i) and imaginary (q) parts of a SLC image with Snap ?

Yes, in most cases. Can you please specify your question? What data you use, for example.

i use SLC images from Sentinel-1 for deformation maping and i want to display the real and imaginary part of the SLC image. I try this with the band math but i not sure that is correct

i and q are already stored as bands, so I see no need to use the band maths for this. Simply double click the bands to display them.