Ping graph

The Ping graph is a line plot of data values against depth for all data points in a single ping or a selection of pings. The Ping graph can be added to an auto-synchronization group. An auto-synchronized ping graph can move through successive pings using graph keyboard shortcuts and can respond to a drag of the ping locator that appears on auto-synchronized single beam echograms. A ping graph will also update when Shortcut menu, Synchronize A or Shortcut menu, Synchronize To Point is used on an echogram. These behaviors can be useful during investigative analyses of single targets, schools or other features in hydroacoustic data. These graphs will update with changes in Echogram mode, and Transducer and Platform Properties.

To display a ping graph for a single ping:

1. Point at the required ping.

2. On the Shortcut (right-click) menu, click Graph Ping.

To display a graph for a selection of pings:

1. Make a selection using the vertical band tool .

2. On the Shortcut (right-click) menu, click Graph Ping.

Notes:

• For angular position variables, each ping will produce two lines on the graph, one for the minor-axis angle, the other for the major-axis angle.
• The maximum and minimum depths for a ping graph are controlled by the depth values of the initial selection on the echogram. When an echogram is zoomed-in, the associated ping graph can't zoom-out.

Display a Sv TVG Curve

This feature is available for Sv variables only. It enables you to plot on the Ping graph the TVG function based on a user-defined value for Sv at 1m (dB).

To display the Sv TVG Curve:

1. Display a ping graph.

2. On the Shortcut menu, select Show Sv TVG Curve.

The curve is affected by the Absorption on the Calibration page of the Variable Properties dialog box for the variable.

Right-click on the Ping Graph and adjust the Sv at 1m (dB) value.

Sv TVG Curve algorithm

The algorithm is:

where:

Y	=	Sv TVG algorithm value evaluated at R (m).
Value_at_R = 1m	=	Value for Sv at 1m (dB) as specified on the Shortcut menu of the Ping Graph.
ξ	=	20 (the TVG range coefficient for Sv Output)
R	=	The corrected range R (m) of the data point. The TVG range correction factor is specified on the Calibration page of the Variable Properties dialog box.
α	=	Absorption coefficient (dB/m) specified on the Calibration page of the Variable Properties dialog box.

Depth values are calculated according to the data's Transducer geometry and algorithms on About depth, range and altitude.

See also

About graphs
About graph shortcuts
About setting variable properties
Using a SoundSpeedProfile: Notes