Quick Start and Tutorials#

This is a collection of simple examples on how to perform specific tasks using the SCT software, both from the CLI interface and as a python library.

Point Target Analysis#

To perform a Point Target Analysis using SCT CLI, run the following command in your shell, adapting the input parameters to your needs. Passing the input configuration can be avoided if default values are good enough.

sct --config path_to_config_toml target-analysis -p path_to_product -out path_to_output_folder -pt path_to_target_csv_file [-eo path_to_external_orbit] [-g]

If an external orbit must be used for a Sentinel-1 product, it can be passed as input to the CLI tool using the –external-orbit/-eo option. Graphical output for point target analysis can be enabled using the –graphs/-g option for the CLI tool.

The exact same thing can be done from a custom script using SCT as a library:

from sct.configuration.sct_configuration import SCTConfiguration
from sct.analyses.point_target_analysis import point_target_analysis_with_corrections
from sct.analyses.graphical_output import sct_pta_graphs  # optional, for graphs only

# adding a configuration is optional
config_toml_path = ...
config = SCTConfiguration.from_toml(config_toml_path)
# adding an external orbit for Sentinel 1 products is optional
path_to_external_orbit = ...
product_path = ...
targets_csv_file_path = ...
output_results_csv_file = ...
graphs_output_directory = ...

results_df, data_for_graphs = pta.point_target_analysis_with_corrections(
    product_path=prod,
    external_target_source=targets_csv_file_path,
    external_orbit_path=path_to_external_orbit,  # optional
    config=config.point_target_analysis,  # optional
)
results_df.to_csv(output_results_csv_file, index=False)

# optional, if graphical output is needed
sct_pta_graphs(graphs_data=data_for_graphs, results_df=results_df, output_dir=graphs_output_directory)

Using external Ionospheric and Tropospheric Maps to compute perturbations#

Input configuration file must contain the following lines to be able to perform a Point Target Analysis taking into account atmospheric perturbations from external maps.

# both or just one of the two perturbations can be selected
[point_target_analysis.corrections]
enable_ionospheric_correction = true
enable_tropospheric_correction = true

[point_target_analysis.corrections.ionosphere]
ionospheric_maps_directory = "path/to/ionospheric/maps/directory"
ionospheric_analysis_center = "cor"

[point_target_analysis.corrections.troposphere]
tropospheric_maps_directory = "path/to/tropospheric/maps/directory"
tropospheric_map_grid_resolution = "fine"

Using ETAD products for Sentinel-1 data#

Input configuration file must contain the following lines to be able to perform a Point Target Analysis taking into account an external ETAD products to compute perturbations.

[point_target_analysis.corrections]
enable_etad_corrections = true
etad_product_path = "path/to/etad/product"

Radiometric Analysis#

To perform a Radiometric Analysis using SCT CLI, run the following command in your shell, adapting the input parameters to your needs. Passing the input configuration can be avoided if default values are good enough.

Note

Input radiometric quantity of the product is set to be BETA_NOUGHT by default. This property can be changed via configuration by adding [radiometric_analysis] input_quantity = "sigma_nought" inserting the proper radiometric quantity.

sct --config path_to_config_toml radiometric-analysis [nesz/elevation_profile/scalloping] -p path_to_product -out path_to_output_folder [-g] [-r "output_radiometric_quantity"]

Graphical output for radiometric analysis can be enabled using the –graphs/-g option for the CLI tool.

Average radiometric profiles output radiometric quantity can be setup by using the –output_radiometric_quantity/-r option.

Validation

output_radiometric_quantity maps to an internal enum class.
Here are the possible values:
input_type: beta, sigma, gamma

The exact same thing can be done from a custom script using SCT as a library:

from pathlib import Path
from sct.configuration.sct_configuration import SCTConfiguration
import sct.analyses.radiometric_analysis as ra
from arepyextras.quality.radiometric_analysis.support import radiometric_profiles_to_netcdf  # optional, if netCDF saving is needed
from arepyextras.quality.radiometric_analysis.graphical_output import radiometric_2D_hist_plot  # optional, if graphs are needed
from arepyextras.quality.core.generic_dataclasses import SARRadiometricQuantity

# adding a configuration is optional
config_toml_path: str | Path = ...
config = SCTConfiguration.from_toml(config_toml_path)
# specify the input radiometric quantity if different from BETA NOUGHT
config.radiometric_analysis.base_config.input_quantity = SARRadiometricQuantity.SIGMA_NOUGHT
product_path: str | Path = ...
output_directory: str | Path = ...
output_radiometric_quantity = SARRadiometricQuantity.GAMMA_NOUGHT

tag = "nesz"
results = ra.nesz_analysis(product_path=product, config=config.radiometric_analysis)
# or
tag = "average_gamma"
results = ra.average_elevation_profile_analysis(
    product_path=product,
    output_quantity=output_radiometric_quantity,
    config=config.radiometric_analysis
)
# or
tag = "scalloping"
results = ra.scalloping_analysis(product_path=product, config=config.radiometric_analysis)

for item in results:
    radiometric_profiles_to_netcdf(data=item, out_path=output_directory, tag=tag)

    # optional, if graphical output is needed
    radiometric_2D_hist_plot(
        data=item,
        out_dir=output_directory,
        title=f"{tag.upper()} Profiles {item.swath} {item.polarization.name}",
    )

Interferometric Analysis#

To perform an Interferometric Analysis using SCT CLI, run the following command in your shell, adapting the input parameters to your needs. Passing the input configuration can be avoided if default values are good enough.

Note

Coherence computation is disabled by default for a single product input (while it’s enabled when two products are provided). To enable its computation, provide a config with [interferometric_analysis] enable_coherence_computation = true.

sct --config path_to_config_toml interferometric-analysis -p path_to_product -out path_to_output_folder -pp path_to_second_product [-g]

Graphical output for interferometric analysis can be enabled using the –graphs/-g option for the CLI tool.

The exact same thing can be done from a custom script using SCT as a library:

from pathlib import Path
from arepyextras.quality.interferometric_analysis.graphical_output import generate_coherence_graphs
from arepyextras.quality.interferometric_analysis.support import coherence_histograms_to_netcdf

from sct.analyses import interferometric_analysis as interf
from sct.configuration.sct_configuration import SCTInterferometricAnalysisConfig

product_path: str | Path = ...
output_dir: str | Path = ...
config = SCTInterferometricAnalysisConfig()
config.base_config.enable_coherence_computation = True

output = interf.interferometric_coherence_analysis(product_path=prod, config=config)
for out in output:
    generate_coherence_graphs(out, output_dir=out_dir, mode="magnitude")
    generate_coherence_graphs(out, output_dir=out_dir, mode="phase")
    coherence_histograms_to_netcdf(out, output_dir=out_dir)