Several context-sensitive pages in the Variable Properties dialog box are displayed for virtual variables. The pages that are displayed depend on the operator that was used to create the virtual variables.
One or more of the following virtual variable pages will be present if Single target manipulation operators have been used:
ST Union, ST Difference, or ST Intersection (Single target manipulation) pages
Target length page
Target property threshold
TS Substitution page
Filter Single Targets page
One of these pages is displayed on the Variable Properties dialog box if a Single target manipulation operator has been applied to create the selected virtual variable.
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.
|
Setting |
Description |
|
Maximum distance between target detections |
Enter the maximum distance value for the operator. The distance is calculated in real world co-ordinates, see About Transducer Geometry for more information. |
The Target length page is displayed on the Variable Properties dialog box if the Target length calculator operator has been applied to create the selected virtual variable.
|
Setting |
Description |
|
Factor A |
Enter the species specific factor A. |
|
Factor B |
Enter the species specific factor B. |
The Target property threshold page is displayed on the Variable Properties dialog box if the Target property threshold operator has been applied to create the selected virtual variable.
|
Settings |
Description |
|
Threshold targets by |
Select a listed target property to threshold the targets operand with. Target properties include:
See About target properties for more details. |
|
Apply minimum threshold |
The minimum threshold for the selected target property. |
|
Apply maximum threshold |
The maximum threshold for the selected target property. |
The TS Substitution page is displayed on the Variable Properties dialog box if the TS substitution operator has been applied to create the selected virtual variable.
|
Setting |
Description |
|
Populate TS with values from: |
Select a set of values from the list to substitute into the TS values of the virtual variable. The additional setting is used to convert the values in the selected field to dB. |
| Set no data values to: |
Select a value from the list to set no data values to. The Zero (-999dB) value is useful when you want to view targets that have this special value. See View target length and target length manual together for more information. |
|
Convert values from linear to dB scale |
Treats the selected set of values as linear and converts them to dB. |
|
Populate Uncompensated TS with values from: |
Select a set of values from the list to substitute into the Uncompensated TS values of the virtual variable. The additional setting is used to convert the values in the selected field to dB. |
| Set no data values to: |
Select a value from the list to set no data values to. The Zero (-999dB) value is useful when you want to view targets that have this special value. See View target length and target length manual together for more information. |
|
Convert values from linear to dB scale |
Treats the selected set of values as linear and converts them to dB. |
Note: The major-axis angle and minor-axis angle refer to the major-axis angle and minor-axis angle at the geometric center of the target detected during multibeam target detection.
About virtual variables
Operators
Variable Properties dialog box
Filter Single Targets page