[gdal-dev] Sentinel-1 IW Single Look Complex (SLC)

ni hao ni_hao88 at hotmail.com
Thu Feb 3 17:26:34 PST 2022


ds=gdal.Open('manifest.safe')
ds.GetRasterBand(1).ReadAsArray(5000, 6000, 10, 6)=
array([[ 8. +7.j,  6.+10.j, -3. +5.j, -3. -1.j, -6. -1.j, -2. -1.j,
         3. +0.j, -2. +0.j, -5. -3.j, -1. -1.j],
       [ 7. +0.j,  4. +0.j, -1. +1.j, -4. +2.j, -1. +0.j, -5. +0.j,
        -1. +2.j,  1. +0.j, -4. +2.j,  5. +0.j],
       [ 0. -6.j,  0. -8.j,  2. -3.j, -1. +3.j,  3. +3.j, -3. +0.j,
        -4. +1.j,  2. +1.j,  0. +6.j,  6. +1.j],
       [-5. -7.j, -3.-10.j,  4. -3.j,  2. +1.j,  4. +3.j,  2. +2.j,
        -2. +0.j,  1. +1.j,  3. +4.j,  0. +1.j],
       [-6. -3.j, -3. -2.j,  1. +0.j,  4. +0.j,  1. +0.j,  4. +3.j,
         2. -1.j,  0. +0.j,  4. +0.j, -4. -1.j],
       [-2. +4.j, -3. +7.j, -3. +2.j,  2. -1.j, -1. -3.j,  2. +1.j,
         4. +0.j, -1. -1.j,  3. -4.j, -4. -3.j]], dtype=complex64)

ds2=gdal.Open('measurement/s1a-iw3-slc-hh-20180215t214409-20180215t214434-020623-0234f6-003.tiff')
ds2.GetRasterBand(1).ReadAsArray(5000, 6000, 10, 6)=
array([[  21. -4.j,  110.+28.j,  154.-24.j,   76.-65.j,  -32.-72.j,
        -104.-77.j, -114.-34.j,  -78. +4.j,  -45.-37.j,  -15.-55.j],
       [  40. -3.j,  -48.-34.j, -164.+21.j, -149.+49.j,  -78.+23.j,
          -1.+32.j,   90.+33.j,  127.-12.j,  119.-18.j,  144. -1.j],
       [ -59. +5.j,   26.+82.j,  124.+47.j,  124.-48.j,   84.-38.j,
          27.+18.j,  -55.+28.j,  -93.+37.j, -112.+51.j, -158.+39.j],
       [ -31. +0.j,  -90.-49.j,  -78.-50.j,  -37.+35.j,   -5.+51.j,
          26.-21.j,   30.-38.j,   25.-25.j,   58.-63.j,   45.-66.j],
       [ 107.+20.j,   64.+30.j,   16.+46.j,   15. -3.j,    4.-56.j,
         -19.-45.j,   -1.-21.j,    0.+10.j,  -29.+59.j,   23.+57.j],
       [ -77. -1.j,   -8.-50.j,   -9.-63.j,  -32.-10.j,  -27.+30.j,
         -32.+36.j,  -33.+22.j,    2.-10.j,   25.-18.j,    2.-11.j]], dtype=complex64)

as you can see, not only SAFE driver can only ingest 1 TIFF out of 3. Its complex numbers are wrong.

________________________________
From: gdal-dev <gdal-dev-bounces at lists.osgeo.org> on behalf of ni hao <ni_hao88 at hotmail.com>
Sent: February 3, 2022 10:11 AM
To: Even Rouault <even.rouault at spatialys.com>; gdal-dev at lists.osgeo.org <gdal-dev at lists.osgeo.org>
Subject: Re: [gdal-dev] Sentinel-1 IW Single Look Complex (SLC)

Hi List,

I downloaded the 3.4.1 and python binding (python 3.6)
Tested on an IW SLC product contains one image per sub-swath, for a total of 3 tiff for HH.

It still only shows one raster band: the first TIFF, rather than three.
Although ds.GetSubDatasets() shows three: IW1, IW2, IW3

ds=gdal.Open('manifest.safe')

>>> ds.RasterCount
1
>>> ds.GetSubDatasets()
[('SENTINEL1_CALIB:SIGMA0:manifest.safe:IW1_HH:INTENSITY', 'Single band with IW1 swath and HH polarization and SIGMA0 calibration'), ('SENTINEL1_CALIB:BETA0:manifest.safe:IW1_HH:INTENSITY', 'Single band with IW1 swath and HH polarization and BETA0 calibration'), ('SENTINEL1_CALIB:GAMMA:manifest.safe:IW1_HH:INTENSITY', 'Single band with IW1 swath and HH polarization and GAMMA calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW1_HH:COMPLEX', 'Single band with IW1 swath and HH polarization and UNCALIB calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW1_HH:INTENSITY', 'Single band with IW1 swath and HH polarization and UNCALIB calibration'), ('SENTINEL1_CALIB:SIGMA0:manifest.safe:IW2_HH:INTENSITY', 'Single band with IW2 swath and HH polarization and SIGMA0 calibration'), ('SENTINEL1_CALIB:BETA0:manifest.safe:IW2_HH:INTENSITY', 'Single band with IW2 swath and HH polarization and BETA0 calibration'), ('SENTINEL1_CALIB:GAMMA:manifest.safe:IW2_HH:INTENSITY', 'Single band with IW2 swath and HH polarization and GAMMA calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW2_HH:COMPLEX', 'Single band with IW2 swath and HH polarization and UNCALIB calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW2_HH:INTENSITY', 'Single band with IW2 swath and HH polarization and UNCALIB calibration'), ('SENTINEL1_CALIB:SIGMA0:manifest.safe:IW3_HH:INTENSITY', 'Single band with IW3 swath and HH polarization and SIGMA0 calibration'), ('SENTINEL1_CALIB:BETA0:manifest.safe:IW3_HH:INTENSITY', 'Single band with IW3 swath and HH polarization and BETA0 calibration'), ('SENTINEL1_CALIB:GAMMA:manifest.safe:IW3_HH:INTENSITY', 'Single band with IW3 swath and HH polarization and GAMMA calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW3_HH:COMPLEX', 'Single band with IW3 swath and HH polarization and UNCALIB calibration'), ('SENTINEL1_CALIB:UNCALIB:manifest.safe:IW3_HH:INTENSITY', 'Single band with IW3 swath and HH polarization and UNCALIB calibration')]
________________________________
From: Even Rouault <even.rouault at spatialys.com>
Sent: February 1, 2022 12:33 PM
To: ni hao <ni_hao88 at hotmail.com>; gdal-dev at lists.osgeo.org <gdal-dev at lists.osgeo.org>
Subject: Re: [gdal-dev] Sentinel-1 IW Single Look Complex (SLC)


Hi,

There have been improvements in GDAL 3.4.0 (*) regarding SLC products in the SAFE/Sentinel 1 driver. I can see that it seems to work fine on a S1A_IW_SLC__xxxx dataset. I don't have EW SLC products at hand

Even

(*) https://github.com/OSGeo/gdal/commit/eea55bfcfd36c081b8354b0a4e132cfc51332ef8

Le 01/02/2022 à 17:26, ni hao a écrit :
Hi list,

GDAL Sentinel-1 driver question:
I know that GDAL Sentinel-1 driver works well on GRD (detected).
What about SLC?

Level-1 IW SLC product contains one image per sub-swath, per polarisation channel, for a total of three or six images (3 tiff for HH, or 6 tiff for HH/HV dual-band)
The EW SLC products contain one image per sub-swath, per polarisation channel, for a total of five or ten images.

https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/single-look-complex

Thank you.



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