Line Properties dialog box

The Line Properties dialog box is used to change the properties of lines, including:

changing the line name
setting line extension values for live viewing
setting line values used to recalculate a selection on an editable line
changing the formula used to define a virtual line
changing the input operands used to create the virtual line
adding notes
setting line visibility for specified acoustic variables
changing calibration settings for sounder-detected bottom lines

To display the Line Properties dialog box:

Display the Dataflow window
Display a view that includes a line
Select a Line
On the Shortcut menu (right-click), click Line Properties

- OR -

Display an Echogram
Point to a line
On the Shortcut menu (right-click), click Line Properties

- OR -

On the Echogram tools toolbar, click the Line and Surface tool arrow and select Active Line Properties. Properties for the active line will be displayed.

The following pages can appear on the Line Properties dialog box:

Raw line Properties pages	Editable line Properties pages	Virtual line Properties pages
Display Calibration Visibility Notes	Source Display Visibility Notes	Operands Arithmetic Best Bottom Candidate Line Pick Crop Display Fixed Depth Linear Offset Maximum Sv Line Pick Near-field depth estimation Notes Off-axis Angle Offset Span Gaps Smoothing Filter Statistical Combination Time Offset Threshold Offset Towed Body Time Offset Trained model bottom exclusion (experimental) Visibility

Operands page

The Operands page is displayed on the Line Properties dialog box for virtual lines only.

Settings

Description

Operator

The operator that is being applied to create the virtual line. This cannot be changed.

Operand(s)

The line, lines or variable that are used to create the virtual line. Use the Operand list arrow to select an operand.

When available click Add New Operand to add an operand or click Remove Last Operand to remove an operand.

The Description section displays the on screen description of the operator.

A description of the behavior of each operator can be found in Operators: Line operators.

The Source page is displayed on the Line Properties dialog box for editable lines only. The settings on the page specify line settings for live viewing and for the recalculation or repick of line sections.

The following settings are available:

Settings

Description

Line source

Displays the line source to use when:

a line is automatically extended as new data arrives during live viewing
a line is recalculated using Recalculate Line or Repick Line on the Shortcut menu.

The line source list can include:

None	Select this option to specify that you want: the line not to extend during live viewing no line to be used when creating a line or recalculating/repicking a selection
Offset from line	Select this option to create a line based on an existing line. The Offset line is specified a selection from the Offset line list. The offset settings specified are under the Offset section. It will continue to create line as new data is received during live viewing. It will apply the offset line settings for the specified selection.
Fixed depth	This option will create a fixed depth line. The fixed depth is specified by a value entered below the Line source setting. It will continue the fixed depth line as new data is received during live viewing. It will use the value of Depth for the specified selection.
Line pick from variable	This option will pick a line on a specified acoustic variable. Click Properties to view or modify the line pick settings on the Single beam tab of the Lines and Surfaces page of the EV File Properties dialog box. Select a Variable on which to run the line pick from the Variable list. It will continue to pick the line as new data is received during live viewing. It will pick the line based on the data in the selected Variable. It will pick the line for the specified selection.

Offset

Specifies the type of line offset to apply to the Offset line.

Select one of:

Linear function

The linear function specifies a Multiply depth by: value and/or a Then add (m) (depth) value for the Offset line.

Off-axis angle

The Off-axis angle function applies an off-axis angle line offset to the Offset line.

The Off-axis angle makes a translated copy of the existing line by calculating the equivalent depth change for a specified change in off beam axis angle. This calculation importantly assumes a vertically oriented echosounder and a flat bottom. The transducer draft only is taken from the specified Transducer. See About off-axis angle line offsets for a precise definition.

General

Span gaps

Select Span gaps to span gaps in the line.

If the extension is based on a sounder-detected bottom and depth data does not arrive as expected, the extension will stop until depth data is received at which point a line segment with a line status of Unverified will connect the last received depth to the new one.

If the extension is based on another line then any gap in that line will be bridged (in the extension to this line) by a line segment with a line status of Unverified.

Otherwise, this option has no effect.

Calibration page

The Calibration page is available for sounder-detected bottom lines and is used to display settings that are used in calculations for the conversion of (line segment) range to depth.

Setting

Description

Transducer

The sounder-detected bottom line is associated with a transducer. Select a Transducer from the Transducer list. A Transducer object in the Dataflow window allows you to configure a transducer. The Transducer Properties allow you to record general information, and enter settings for transducer location and orientation.

Edit the calibration file used by this fileset

This hyperlink is only available when an ECS file has been added to the fileset. Use the hyperlink to Edit the ECS file.

Note: An ECS file may affect multiple EV files or multiple variables. For more information refer to Echoview Calibration Supplement files.

SourceCal

Refer to the SourceCal entry.

LocalCal

Refer to the LocalCal entry.

Settings

Displays calibration settings that Echoview uses for calculations.

Echoview handles an extensive range of calibration settings, a complete list (including default values, units and ranges) can be found under Help menu > Calibration Information. Only a subset of these are relevant to your data. Echoview knows a setting is relevant when it reads it from a data or ECS file, or uses it in a calculation. These are the ones that were read from the variable's own calibration source in the data file, or explicitly associated with the fileset or calibration source in the ECS file.

The Line Properties Calibration page only displays the calibration settings that are relevant to the raw line variable.

The Used by segments section displays the applicable line segments for the displayed calibration settings.

The Value column lists the values used in calculation.

The Calibration file column lists the values read from the ECS file in the fileset.

The Data file column lists the values read from the data files in the fileset.

Calibration setting text color	Description
Black	A calibration setting that is set in either a data file or the ECS file, and has been used in a calculation.
Orange	A default calibration setting that Echoview has used in a calculation. The setting was not set in a data or ECS file. Default values may make your data invalid.
Grey	A calibration setting that is set in either a data file or the ECS file, and has not been used in a calculation.

For a technical description of the various calibration settings please consult:

Notes:

The setting colors are based on the processing that has been done since the data and ECS files were last loaded. If you reload the ECS file, after changing some values for example, you may find that some settings revert to grey. This is because Echoview has not found the need to use them since the re-load. Recalculate or step through the pings in the echogram to use any newly modified settings.
You can Copy displayed Calibration settings and Paste them into an ECS file.
A warning message is sent to the Messages dialog box when the calibration settings read from the data files in the fileset vary between pings. There will then be more than one Used by segments group. With respect to the line variable, it is the line points and as a result line segments that are affected by ping calibration.

Visibility page

The Visibility page of the Line Properties dialog box is used to select (or clear) the visibility of the line for an acoustic variable. You can set the line's visibility for all acoustic variables or no variables or selected variables. The settings on the Lines page of the Variable Properties dialog box can change line visibility as well. A colored checkbox indicates that the line is used by the variable.

Display page

The Display page of the Line Properties dialog box is used to specify line thickness and line status color for a line variable. Alternatively, line thickness and line status colors for all lines in the EV file may be changed in the Line display defaults section of the Echogram page of the EV File Properties dialog box.

Available settings:

Settings

Description

Default

Uses the default line thickness and line status colors.

Custom

Select Custom to specify the thickness and color of the line status in a line. Click a line status color to display a color palette and choose a new color.

Line status colors that can be changed include:

Good
Bad
Uncertain

Thickness specifies line thickness in pixels.

Notes page

The Notes page of the Line Properties dialog box is used to change the Name of a line, display the Line type of the line and add Notes. Use Reset to assign a default name.

See also: Notes for name uniqueness and supported characters in a name.

Arithmetic

The Arithmetic page is displayed on the Line Properties dialog box if the Arithmetic operator has been applied to create the selected virtual line.

Available algorithms include:

Add (line) depths
Subtract (line) depths

Best Bottom Candidate Line Pick page

The Best Bottom Candidate Line Pick page is displayed on the Line Properties dialog box if the Best bottom candidate line pick operator has been applied to create the selected virtual line.

This page displays the following Best bottom candidate settings:

Setting	Description
Start depth (m)	Determines at what depth (m) the Line picking algorithm will start, i.e. data above this depth will not be considered. This is particularly useful if you have high return areas at the top of your echogram that you wish to avoid being picked as bottom.
Stop depth (m)	Determines at what depth (m) the Line Picking algorithm will stop i.e. data below this depth will not be considered.
Minimum Sv for a good pick (dB)	See Best bottom candidate settings description for details.
Use Backstep	When checked the Discrimination level and Backstep range settings are available.
Discrimination level (dB)	See Best bottom candidate settings description for details.
Backstep range (m)	See Best bottom candidate settings description for details.
Peak threshold (dB)	See Best bottom candidate settings description for details.
Maximum dropouts (samples)	See Best bottom candidate settings description for details.
Window radius (samples)	See Best bottom candidate settings description for details.
Minimum peak asymmetry	See Best bottom candidate settings description for details.

See Line Pick algorithms for more details.

Crop

The Crop page is displayed on the Line Properties dialog box if the Crop operator has been applied to create the selected virtual line.

Settings	Description
Crop above depth (m)	Specifies the minimum depth (m) to crop the operand line.
Crop below depth (m)	Specifies the maximum depth (m) to crop the operand line.

Notes:

The virtual line will have the same number of time/depth coordinates as the input operand.
Line time/depth coordinates outside the Crop above depth and Crop below depth are assigned a line status of None.
This operator may be useful for lines in high frequency data. See Statistical combination algorithm page: Before you begin for more information.

Maximum Sv Line Pick page

The Maximum Sv Line Pick page is displayed on the Line Properties dialog box if the Maximum Sv line pick operator has been applied to create the selected virtual line.

This page displays the Maximum Sv settings:

Setting	Description
Start depth	Determines at what depth (m) the Line picking algorithm will start, i.e. data above this depth will not be considered. This is particularly useful if you have high return areas at the top of your echogram that you wish to avoid being picked as bottom.
Stop depth	Determines at what depth (m) the Line Picking algorithm will stop i.e. data below this depth will not be considered.
Minimum Sv for good pick (dB)	This setting specifies the minimum Sv (dB) value for good line status for the Line pick algorithm.
Use Backstep	When checked the Discrimination level and Backstep range settings are available.
Discrimination level	Specifies the Discrimination level (dB) for the Maximum Sv algorithm.
Backstep range	Specifies the Backstep range (m) for the Maximum Sv algorithm.

See Line Pick algorithms for more details.

Fixed Depth page

The Fixed Depth page is displayed on the Line Properties dialog box if the Fixed depth operator has been applied to create the selected virtual line.

Setting	Description
Depth	Enter the depth, in meters, of the virtual line.

Linear Offset page

The Linear Offset page is displayed on the Line Properties dialog box if the Linear offset operator has been applied to create the selected virtual line.

Settings	Description
Multiply depth by	Enter a value to multiply the depth of the operand line by.
Then add (m)	Enter a value, in meters, to add to the resulting line.

Near-field Depth Estimation page

The Near-field Depth Estimation page is displayed on the Line Properties dialog box if the Near-field depth estimation operator has been applied to create the selected virtual line.

Settings	Description
Multiply near-field range by	This is a factor by which to extend the near-field range that Echoview computes. The multiplier is applied in the range dimension then values are converted to depth. The default value is 2.

Off-axis Angle Offset page

The Off-axis Angle Offset page is displayed on the Line Properties dialog box if the Off-axis angle offset operator has been applied to create the selected virtual line.

Settings	Description
Transducer	Select the transducer that will be used in the off-axis angle offset calculation.
Angle (degrees)	Enter the angle, in degrees, that will be used to apply an off-axis offset to the input operand.

See About off-axis angle line offsets for a more detail on how the Angle and Transducer settings are used.

Span Gaps page

The Span Gaps page is displayed on the Line Properties dialog box if the Span gaps operator has been applied to create the selected virtual line.

Settings	Description
Line status	Sets the selected line status for the bridging line segments in the virtual line.
Maximum gap size (seconds)	Sets the maximum time between gaps to be bridged.

Smoothing Filter page

The Smoothing Filter page is displayed on the Line Properties dialog box if the Smoothing filter operator has been applied to create the selected virtual line. Smoothing is evaluated for a serially applied smoothing window.

Settings

Description

Smoothing mode

Determines the smoothing applied to the window (whose size is specified by the Number of points) for the operand line.

Select a Smoothing mode:

Maximum	Determines the maximum depth value of the sampled points in the operand line. Output line points (in the concurrent window) take on this value.
Mean	Determines the average depth value of the sampled points in the operand line. Output line points (in the concurrent window) take on this value.
Median	Determines the median depth value of the sampled points in the operand line. Output line points (in the concurrent window) take on this value.
Minimum	Determines the minimum depth value of the sampled points in the operand line. Output line points (in the concurrent window) take on this value.

Number of points (window size)

Specifies the size of the smoothing window for operand line. Enter an odd number between 1 and 251. A larger smoothing window may increase the processing time.

The applied Smoothing mode gives the depth value for the matching line points in the virtual line.

Note: A window size of 1 will create a virtual line the same as the operand line; no smoothing will occur.

Notes:

The output point will be assigned the same line status as the central input point.
If the central input point has no depth value then the output point will have no depth value.
If the window contains points with no depth value, other than the central input point, they will be not be included in the calculation.
At the start and end of the line, the window will be truncated at the boundary to the number of available points in the input line. This will result in fewer points being sampled on that side of the input point.
The Smoothing filter operator can only apply smoothing with respect to the time/depth coordinate points of the operand lines. Operand lines with few or irregularly spaced coordinate points may produce an unsatisfactory line (that differs from the expected line).

Statistical Combination

The Statistical Combination page is displayed on the Line Properties dialog box if the Statistical combination operator has been applied to create the selected virtual line.

Settings

Description

Statistic

Determines the statistical operation to apply to the operand lines (selected on the Operands page).

Select one of:

	Mean depth	The mean depth of the operand lines is output to the virtual line.
	Minimum depth	The minimum depth of the operand lines is output to the virtual line.
	Median depth	The median depth of the operand lines is output to the virtual line.
	Maximum depth	The maximum depth of the operand lines is output to the virtual line.

Divergence

Check Limit divergence to apply a divergence limit to the input depths.

Enter a value in meters for Divergence limit.

Divergence is defined as the difference of any one operand line's depth from the mean of all the operand depths, at a time T. If any operand lines have depths that exceed the Divergence limit, those lines will be ignored in the calculation of the output line at time T.

See Statistical_combination_operator algorithm for more details.

Time Offset

The Time Offset page is displayed on the Line Properties dialog box if the Time offset operator has been applied to create the selected virtual line.

Settings	Description
Time offset	Select the time offset operation. The operator can Add or Subtract the specified time from the operand line.
Days	Specify the number of days to offset.
Hours	Specify the number of hours [0, 23] to offset.
Minutes	Specify the number of minutes [0, 59] to offset.
Seconds	Specify the number of seconds [0, 59] to offset.
Milliseconds	Specify the number of milliseconds [0, 999] to offset.

Threshold Offset

The Threshold Offset page is displayed on the Line Properties dialog box if the Threshold offset operator has been applied to create the selected virtual line. The threshold offset detection looks for the first boundary sample in a ping, with reference to the Operand 2 (base) line. A boundary may delineate vegetation, transducer ring down, bubbles near the transducer or some other water column feature.

Refer to About the Threshold offset operator and the Threshold offset algorithm for more information.

Settings	Description
Detect minimum threshold	Detect a threshold that is the minimum value (dB) for a boundary. Enter the value under Threshold (dB). This setting is normally used when the base line to boundary feature varies from high to low dB value.
Detect maximum threshold	Detect a threshold that is the maximum value (dB) for a boundary. Enter the value under Threshold (dB). This setting is normally used when the base line to boundary feature varies from low to high dB value.
Allow detection from echogram extents	Select this setting when the operand line is beyond the operand variable extents. The Threshold offset algorithm will begin the detection at the operand variable extent.
Apply line-relative smoothing to the echogram data	Select Apply line-relative smoothing to the echogram data to apply a 3x5 Blur convolution with the center of the kernel set to 1. Note that range changes between pings may result in unexpected smoothing. Smoothing increases the processing time.
Minimum accepted distance (m)	The Minimum accepted distance value specifies a minimum boundary distance for boundary samples. The default value is 0 meters. A ring down boundary detection benefits from the default value. A vegetation boundary detection from a bottom line may be more successful with a small non-zero Minimum accepted distance. In this case, areas with a height less than Minimum accepted distance are ignored.
Maximum detection distance (m)	The Threshold offset detection will not detect beyond this specified distance in depth from Operand 2 in the Direction of detection.
Direction of detection	The Direction of detection from the line operand may be specified as Above operand line or Below operand line.

Towed Body Time Offset

The Towed Body Time Offset page is displayed on the Line Properties dialog box if a Towed body time offset operator has been applied to create a virtual line. The operator creates a virtual line for the visualization of a towed body's position using an acoustic variable and a depth line. Operand 1 is an acoustic variable. Operand 2 is a line that represents the depth-time series of the towed body. The output virtual line is a time adjusted depth-time series where offset time is based on ping times of operand 1 and the depth at the offset time. The GPS data specified for the Platform is used to calculate offset times.

Settings	Description
Tow point
X-alongship offset (m)	The platform tow point offset is located from the platform system reference and to the tow point. X -axis tow point offset value is in meters. Negative offset values are towards the aft of the platform. For further information refer to the Towed body time offset diagram and assumptions.
Z- vertical offset (m)	Z-axis tow point offset value in meters. Negaitve is up and positive is down.
Tow line
Fixed length (m)	The tow line is relative to the tow point and is in the alongship direction. Select and specify a value for a fixed tow line length (m).
Varying length (m)	Use the Varying length list to specify a length variable derived from tow line length data.

Trained Model Bottom Exclusion (experimental)

The Trained Model bottom Exclusion page is displayed on the Line Properties dialog box if a Trained model bottom exclusion (experimental) operator is used to create a virtual line. This can be used for data exclusion.

Settings	Description
Detection start range (m)	The operator does not consider ping samples from the above this range (refer to its Line picking algorithm). This allows you to omit phenomena such as the transducer ring down, the near-field zone or surface features as false bottom detections.