Help Content > Interferometric Stacking > Post Processing Tools

Purpose

This tool is used to compute the angular distortion on the input velocities.

Technical Note

The tool analyzes the velocities given a radius defined by the user.

The resulting value is computed with the following formula:

Skew_estimation_formula

Where Adv is the differential settlement on the velocities and l corresponds to the radius.

The resulting value, named Angular distortion (β), is then classified according to the user defined thresholds.

Notes:

•The input file must be a vertical decomposed displacement layer;

•The angular distortion can be computed on an attribute at choice and not only on the default velocity field; to do this, edit the "Shape value field name" located under "Other Parameters."

Input Files

Input Shape Files

The accepted file formats are: Shape file (.shp), SARscape raster format or geodatabase (.gdb).

If the input file is a gdb, it is necessasry to select the ''gdb'' file inside the .gdb folder.
This file is mandatory, the shape and gdb files must contain only point features.

Parameters - Principal Parameters

Radius (m)

Radius size expressed in meters of the moving window centered on every point features.

Low risk class threshold

The threshold for the low risk category. The default value is 0.00033 (1/3000, reference: https://www.sciencedirect.com/science/article/abs/pii/S0034425720305344 ).

Medium risk class threshold

The threshold for the medium risk category. The default value is 0.00066 (1/1500, reference: https://www.sciencedirect.com/science/article/abs/pii/S0034425720305344 ).

High risk class threshold

The threshold for the high risk category. The default value is 0.002 (1/500, reference: https://www.sciencedirect.com/science/article/abs/pii/S0034425720305344 ).

Min number of points in the window

The minimum number of points that have to be included in the radius for the skew to be calculated (min. 3). The higher this number the more precise the value; sparse points may be discarded in case this threshold is not satisfied.

Note: The output file will have four risk category classes: β<0.00033, 0.00033<β<0,00066, 0.00066<β<0.002, 0,002<β

Parameters - Global

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Other Parameters

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Output Files

Output Root Name

Name of the output root. This file is mandatory.

Field description of the generated shape file:

▪x, y, z: coordinates of the point feature, in the same cartographic system of the input file

▪vel_x_comp: Velocity component of the variation along the x axis (East-west direction)

▪vel_y_comp: Velocity component of the variation along the y axis (North-south direction)

▪angle_degr: Direction expressed in degrees of the steepest descent, calculated through the atan2 (y/x)

angle

▪beta: Angular distortion value

▪class: Risk category class

The same fields are created for the gdb file.
The raster output divides the fields into separate files.

General Functions

Exec

The processing step is executed.

Store Batch

The processing step is stored in the batch list. The Batch Browser button allows to load the batch processing list.

The window will be closed.

Help

Specific help document section.

Specific Function(s)

None.