Some algorithms provide --wif parameter to save intermediate results, by default only a final result is saved.
Hence specifying --wif will enable getting intermediate results in the same folder as final result, whereas default behavior
will not produce any extra files.
Final output can be specified with -o argument where directory value does not influence the output name. By default an output name will be
input plus processing steps acronym. One can also define final result filename, then the value should be fully qualified filename, for example:
-o /tmp/S1A_IW_SLC__1SDV_20200904T111450_20200904T111520_034208_03F970_E017_coh_window2010.tif
--help output
Arguments:
-h [ --help ] Print help
-r [ --in_ref ] arg Reference scene's input SAFE dataset
(zipped or unpacked)
-s [ --in_sec ] arg Secondary scene's input SAFE dataset
(zipped or unpacked)
--b_ref1 arg Reference scene's first burst index -
starting at '1', leave unspecified for
whole subswath
--b_ref2 arg Reference scene's last burst index -
starting at '1', leave unspecified for
whole subswath
--b_sec1 arg Secondary scene's first burst index -
starting at '1', leave unspecified for
whole subswath
--b_sec2 arg Secondary scene's last burst index -
starting at '1', leave unspecified for
whole subswath
--orbit_ref arg Reference scene's POEORB/RESORB file.
Can be unspecified.
--orbit_sec arg Secondary scene's POEORB/RESORB file.
Can be unspecified.
-o [ --output ] arg Output folder or filename
-p [ --polarisation ] arg Polarisation for which coherence
estimation will be performed - VV;VH
--sw arg Reference scene's subswath
-a [ --aoi ] arg Area Of Interest WKT polygon, overrules
first and last burst indexes
--dem arg DEM file(s). Only SRTM3 is currently
supported.
--no_mask_cor Do not mask out areas without elevation
in coregistration
--orbit_dir arg Directory of orbit files (restituted
and/or precise). Can be used to find
correct one during processing. Can be
unspecified - hence no orbital
information is updated. Also supports
ESA SNAP compatible folder for example:
/home/<user>/.snap/auxData/Orbits/Senti
nel-1/POEORB/
--srp_number_points arg (=501)
--srp_polynomial_degree arg (=5)
--subtract_flat_earth_phase arg (=1) Compute flat earth phase subtraction
during coherence operation. By default
on.
--rg_win arg (=15) range window size in pixels.
--az_win arg (=0) azimuth window size in pixels, if zero
derived from range window.
--orbit_degree arg (=3)
-w [ --wif ] Write intermediate results (will be
saved in the same folder as final
outcome). NOTE - this may decrease
performance. By default off.
--ll arg (=verbose) Log level, one of the following -
verbose|debug|info|warning|error
--gpu_mem arg (=100) Percentage of how much GPU memory can
be used for processing
For orbit files there are multiple options. If a user has a SNAP installation and has processed the same scenes already, the existing orbit files
can be used by supplying SNAP's orbit file directory e.g. --orbit_dir /home/<user>/.snap/auxData/Orbits/Sentinel-1/POEORB/.
If such option does not exist or there are no specific orbit files present, one can use sentineleof
and then supply downloaded files via --orbit_ref and --orbit_sec. Also orbit files could be collected into directory,
the tool can search for correct one. Supports restituted(RESORB) and precise(POEORB) orbits.
If no orbit arguments are supplied, the orbital information is simply not updated during the calculations.
When specifying an area to be processed traditional subswath and burst index parameters can be used. However, it might be simpler
to use -a/--aoi parameter to specify exact region. This must be a WKT polygon and does not have to follow burst boundaries exactly.
For example a stripe like polygon can be supplied where it will consider all the bursts to be processed which are overlapping with the given coordinates.
Currently a subswath parameter must be supplied (this requirement will be removed in upcoming versions) along with area of interest.
For analyzing scenes' layout and position on map a S-1 TOPS SPLIT Analyzer could be used.
Coherence computation parameters are pure computation specific and further knowledge of these could be found in SNAP Help/Documentation or via some other resources in web. This document here does not discuss specifics of those - since these are algorithm specific math details.
Full subswath (IW1) with orbit files from SNAP aux.
alus-coh -r S1A_IW_SLC__1SDV_20200724T034334_20200724T034401_033591_03E49D_96AA.SAFE \
-s S1A_IW_SLC__1SDV_20200805T034334_20200805T034401_033766_03E9F9_52F6.SAFE \
--orbit_dir ~/.snap/auxData/Orbits/Sentinel-1/POEORB/ --sw IW1 -p VV \
--dem srtm_43_06.tif --dem srtm_44_06.tif -o /tmp/ --ll info
AOI based (3 bursts covered) processing with orbit files and specifying final result filename. Inputs as ZIP files.
alus-coh -r S1B_IW_SLC__1SDV_20210615T054959_20210615T055026_027363_0344A0_83FE.zip \
-s S1A_IW_SLC__1SDV_20210703T055050_20210703T055117_038609_048E45_35F7.zip \
--orbit_ref S1B_OPER_AUX_POEORB_OPOD_20210705T111814_V20210614T225942_20210616T005942.EOF.zip \
--orbit_sec S1A_OPER_AUX_POEORB_OPOD_20210723T121923_V20210702T225942_20210704T005942.EOF.zip \
--sw IW3 -p VV --ll info --dem srtm_37_02.zip --dem srtm_37_03.zip --dem srtm_38_02.zip --dem srtm_38_03.zip \
--aoi "POLYGON ((3.76064043932478 50.6679002753201,4.81930157970497 50.5884971985178,4.65806260842462 50.0309601054367,3.65031903792243 50.1622939049033,3.76064043932478 50.6679002753201))" \
-o /tmp/S1B_IW_SLC__1SDV_20210615T054959_20210615T055026_027363_0344A0_83FE_Orb_Stack_coh_deb_tc_zipped.tif
--help output
-h [ --help ] Print help
-i [ --input ] arg Input SAFE dataset (zipped or unpacked)
-o [ --output ] arg Output folder or filename
-w [ --wif ] Write intermediate results (will be saved in the
same folder as final outcome). NOTE - this may
decrease performance. Default OFF.
-s [ --subswath ] arg Subswath for which the calibration will be
performed, one of the following - IW1;IW2;IW3
-p [ --polarisation ] arg Polarisation for which the calibration will be
performed - VV;VH
--bi1 arg First burst index - starting at '1', leave
unspecified for whole subswath
--bi2 arg Last burst index - starting at '1', leave
unspecified for whole subswath
-a [ --aoi ] arg Area Of Interest WKT polygon, overrules first and
last burst indexes
-t [ --type ] arg Type of calibration to be performed, one of the
following - sigma;beta;gamma;dn
--dem arg DEM file(s). Only SRTM3 is currently supported.
--ll arg (=verbose) Log level, one of the following -
verbose|debug|info|warning|error
--gpu_mem arg (=100) Percentage of how much GPU memory can be used for
processing
Input of the processing is provided by -i/--input argument. The area on which to perform processing can be traditional subswath and burst index parameters.
However, it might be simpler to use -a/--aoi parameter to specify exact region. This must be a WKT polygon and does not have to follow burst boundaries exactly.
For example a stripe like polygon can be supplied where it will consider all the bursts to be processed which are overlapping with the given coordinates.
Currently a subswath parameter must be supplied (this requirement will be removed in upcoming versions) along with area of interest.
-t/--type option specify which kind of calibration is performed - which look-up table is used and normalization formula - to radiometrically calibrate the data.
Gamma calibration of 4 bursts, ZIP SAFE input and specified output name
alus-cal -i $test_dataset_dir/S1A_IW_SLC__1SDV_20210722T005537_20210722T005604_038883_049695_2E58.SAFE \
-o /tmp/S1A_IW_SLC__1SDV_20180815T154813_20180815T154840_023259_028747_4563_Calib_IW1_tc.tif \
--sw IW2 --polarisation VV -t gamma --bi1 2 --bi2 6 \
--dem srtm_51_09.tif --dem srtm_52_09.tif --ll info