Comparing ''converted SLC product (S-1 SLC scene) to GRD'' with ''Original S-1 GRD scene''

Microwave Toolbox
1

Dear all,
I converted SLC product (S-1 SLC scene) to GRD by using the SNAP operator “S1 SLC to GRD” and I want to compare my result with an S-1 GRD scene that exactly corresponds to that S-1 SLC scene. I have some questions about it:
Original S-1 GRD scene:
S1A_IW_GRDH_1SDV_20150525T160305_20150525T160334_006080_007DEF_CEB3
Original S-1 SLC scene:
S1A_IW_SLC__1SDV_20150525T160305_20150525T160335_006080_007DEF_BF84

  1. My result from converted SLC to GRD is like below (sigma0_vv) but GRD sence has two things
    , (intensity and amplitude);
    if I want to compare my converted SLC to GRD (S-1 SLC scene) with GRD sence, shall I compare sigma0-vv with intensity or with amplitude?
    Shall I convert whole to db or not?
  2. I want to merge two products into one, I know it is possible with ‘create stack’ but is there any other way?
  3. I do not know how can I compare results with together and what is their difference? As I can see in images original GRD product does not have below part and is disappeared. Why?
    (look at images)
  4. is it possible extract only one sub-swath from original GRD or not (whole sub-swaths are attached to each other and I do not know how can I detach them)?

Original S-1 GRD scene (intensity):

intensity.png1920×1080 1.06 MB

Original S-1 GRD scene (amplitude):
amplitude.png1920×1080 1.07 MB

Converted SLC scence (exactly corresponds to that S-1 GRD scene) to GRD:
sigma0vv.png1920×1080 1.18 MB

2

Hello,

To my knowledge, intensity is amplitude squared and is a virtual band.
Moreover, you can convert your data to sigma0 by using Radar> Radiometric > Calibrate and in the Processing parameters, there is an option to “output sigma_0”

Regards,
Hasina

3

I agree, you can only compare calibrated products. Furthermore, the GRD data is already multi-looked while the SLC isn’t.

To get them into one product, calibrate both, convert to db, multi-look the SLC to ground range geometry, then use the coregistration tool.

4

Thanks for answer. I have another question;
when I convert ‘sigma0’ to ‘sigma0 in db’, I have these two band in my product (look at below image) but I want to have only ‘sigma0 in db’. I used ‘subset’ for that and I only choose ‘sigma0 in db’ and selected ‘select none’ for ‘Tie point Grid subset’ and ‘metadata subset’, then I got an question (look at below), I answered ‘no’, by this way, I had only ‘‘sigma0 in db’’ but I could not open product and I think there was something wrong with it and when I answered ‘yes’, I had again both ‘sigma0’ and ‘sigma0 in db’in my answer.
I do not know what should I do? I want to have only ‘sigma0 in db’ in my result.

  1. Two ‘sigma0’ and ‘sigma0 in db’ in my result.

  2. I only choose ‘sigma0 in db’.

    7_v_2.png1920×1080 988 KB

  3. I got this text by ‘yes’ and ‘no’ answers.

    7_v_3.png1920×1080 1010 KB

5

to permanently store a db layer, right-click it and select ‘convert band’. It is then no longer logically dependent from the non-db band. Save your product afterwards. You can then

  • use it in the subset dialogue without the warning message or
  • simply delete the non-db raster