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snap_graph.CoherenceConfig

Configuration for the coherence pipeline.

Usage

Source

snap_graph.CoherenceConfig()

Inherits every parameter of GeocodingConfig.

No Multilook step is applied, unlike BackscatterConfig. It would save no runtime, since it can only sit after the coregistration and phase-removal stages that dominate this graph, and placing it after the Coherence operator averages coherence magnitudes and so cannot reduce the small-window estimator bias. Use window to set the looks.

Parameters

window

Coherence estimation window (n_rg, n_az) in single-look samples. This is the only control over the number of looks entering the estimator. SNAP’s squarePixel option, which derives the azimuth window from the range window and the scene geometry, is pinned off, so the window given is the window applied.

subtract_flat_earth_phase

Remove the flat-earth phase before estimating coherence.

subtract_topographic_phase

Remove the topographic phase using dem.

correct_coherence_bias

Remove the positive bias a finite estimation window leaves in the coherence magnitude. Requires SNAP 14; building the graph for an older or undetermined version raises ConfigurationError. Off by default, unlike SNAP’s own default, so that the estimator stays the one the window describes and stays comparable across SNAP versions.

remove_local_phase_ramp
Let SNAP estimate and remove a local phase ramp within each estimation window before averaging, which recovers coherence lost to residual fringes. Requires SNAP 14, as above.

Attributes

Name Description
output_bands Names assigned to the output GeoTIFF bands by the SNAP client.

output_bands

Names assigned to the output GeoTIFF bands by the SNAP client.

output_bands: list[str]

Methods

Name Description
to_xml() Build the coherence graph XML for this config.

to_xml()

Build the coherence graph XML for this config.

Usage

Source

to_xml(*, snap_version=None)
Raises
ConfigurationError
If correct_coherence_bias or remove_local_phase_ramp is enabled but snap_version is older than 14 or unknown.