ST Union

This operator returns all the single targets in the first variable, plus any single targets in the second variable that are not within a specified distance of any target in the first variable.

Echoview accepts operands of the following data types as input:

Operand 1

Operand 2

  • Single targets
  • Single targets


The ST Difference Variable Properties dialog box pages include (common) Variable Properties pages and these operator pages.

Operands page

ST Union page



Maximum distance between target detections

Enter the maximum distance value for the operator.

The distance is calculated in real world coordinates, see About Transducer Geometry for more information.

Warning: If you apply a Single target manipulation operator you must, on the Calibration page of the Variable Properties dialog box for the resulting virtual variable, select the same transducer that was selected for the first operand (input variable). If a different transducer is selected, the results may be misleading.

Note: Single target manipulation operators may calculate incorrect results for single targets when two transducers face each other. A problem arises when single targets of the second operand lie behind the face of the transducer of the first operand. Single targets that lie behind a transducer may have unsupported range and/or unsupported angle values. An example configuration is a seabed up-mounted transducer with an AUV down-mounted transducer moving overhead.

See also

About virtual variables
Operator licensing in Echoview