Getting to know presentation modes and views
The display presentation offered by the SN90system presents several views. Different combinations of views are organized in presentation modes.
Context
The SN90 system presents the echo data in different views. All information from each ping is shown in all the views simultaneously. Each view uses its individual transmit frequency, and you set up the different views with different operating parameters. The presentation of the echoes in each view is calculated based on your present course and speed combined with the movements of the target(s).
The following views are available:
•  Horizontal
•  Vertical
•  Plane
•  Inspection
Tip
With the various beams provided by the SN90 system, it may be difficult to understand the concepts. How do these beams "behave" in the water? By means of a graphic presentation, the Beam Visualization dialog box attempts to give you a better understanding of how the acoustic beams are transmitted into the water. Open the Beam Visualization dialog box from the Setup menu.
Procedure
1 At the bottom of the display presentation, select a suitable presentation mode, and activate the Horizontal view.
The Horizontal view in the SN90 display presentation covers the entire sector of 160 degrees.  
The current bearing is shown with a solid line pointing out from the vessel position. You can change the angle by means of the Bearing function on the Main menu. You can also select the bearing line and drag it sideways.
The bow marker is shown as a dotted line drawn from the bow of the vessel symbol. The line reflects your vessel’s current heading. The bow marker can be enabled or disabled on the Visual Objects menu. Note that the bow marker is only shown with a forward-looking transducer.
The distance from the vessel symbol in the centre of the circle to the outer ring corresponds to the currently selected range.
•  The current settings for range, gain and tilt are shown in the upper left corner of the view. When you change the tilt a dotted line presents the requested tilt while the solid line presents the actual tilt. You can change the tilt angle by means of the Tilt function on the Main menu. You can also click on the tilt line in a Vertical view and drag it up and down.
•  The position (bearing and distance) and depth of the cursor's location is shown in the lower right corner of the view. The depth is calculated from the current tilt and the distance from the vessel.
•  You can see the latest marker's course and speed in the view's lower right corner. The values are calculated based on the last two markers you created and the time between them.
•  Relevant information about a priority target can be found in the lower left corner of the view.
In a horizontal swath the SN90 system transmits with a maximum horizontal opening angle of 160 degrees.  
Using the Horizontal Tx Sector function, you can change this opening angle to 90, 120 degrees.  
The Cosmetics menu controls which "cosmetic" features that used.
2 At the bottom of the display presentation, select a suitable presentation mode, and activate the Vertical view.
The Vertical view shows you a "vertical slice" of the echo data. The direction of the vertical slice is indicated and controlled by the bearing line in the Horizontal view. You can change the bearing on the Main menu. You can also select the bearing line in a Horizontal view and drag it sideways.
The upper horizontal line in the view represents the water surface.
•  Horizontal dotted lines show the depth intervals. Use Depth Dividers on the Cosmetics menu to toggle these lines On or Off.
•  The selected range is divided into identical distances. These are shown as dotted circles. They are referred to as range rings.
•  The distance and depth of the cursor's location is shown in the lower right corner of the view.
The current tilt is shown with a solid line. You can change the tilt angle by means of the Tilt function on the Main menu. You can also click on the tilt line and drag it up and down.
In a horizontal swath the SN90 system transmits with maximum vertical opening angle:  degrees.
By means of the Vertical Tx Sector function, you can change this opening angle to:  degrees.
The Cosmetics menu controls which "cosmetic" features that used.
Tip
During operations in a vertical view you may wish to focus on the echoes in the upper or lower part of the view. Use Vertical Reference to hide a part of the view. When the function is activated, the vertical range depends on the physical height of the view. A taller view gives you a larger visible depth range while the size of the removed range is reduced.
3 At the bottom of the display presentation, select a suitable presentation mode, and activate the Catch view.
Use the information in the Catch view to monitor the progress of the purse seine operation. The view does not offer any echo data.
The progress bar at the top of the Catch view shows you the amount of net that has been spent. The sequence starts when you shoot the net. You must then press Gear on the operating panel or select Place Gear Symbol on the shortcut menu.
The estimated depth of the purse seine is shown under the progress bar. The depth is calculated from the sink rate you have defined for the fishing gear. Under Fishing Gear, select Fishing Gear Setup to open the dialog box. For the selected purse, set the sink rate.
•  Horizontal dotted lines show the depth intervals. Use Depth Dividers on the Cosmetics menu to toggle these lines On or Off.
•  Relevant information about a priority target can be found in the lower left corner of the view.
A line of X’es in the vertical views shows the bottom of the purse seine. The depth is defined for the fishing gear you have chosen. Under Fishing Gear, select Fishing Gear Setup to open the dialog box. For the selected purse, select a depth value. Use Purse Depth on the Cosmetics menu to toggle this line On or Off.
If you have connected a compatible catch monitoring system to your SN90 system, information from these sensors are shown in the Catch view.
4 At the bottom of the display presentation, select a suitable presentation mode, and activate the Echogram view.
The Echogram view provides echo data from a horizontal beam in a common echogram presentation. The echo data is taken from the current bearing and tilt. The beam used to provide data is identified in the top left corner of the view. Horizontal dotted lines show the depth intervals.
•  You can change the bearing on the Main menu. You can also select the bearing line in a Horizontal view and drag it sideways.
•  You can change the tilt angle by means of the Tilt function on the Main menu. You can also click on the tilt line in a Vertical view and drag it up and down.
Left-click in the Echogram view to open the tooltip. The tooltip provides the cursor location in the echogram (slant range, true range and depth) as well as the current pulse duration and time.
The Horizontal Scroll function controls how fast the echo presentation shall move from right towards left in the Echogram and Inspection views. The speed is controlled by adjusting the number of pixels used to present each ping. A higher speed will update the view faster, but will also reduce the resolution.
5 At the bottom of the display presentation, select a suitable presentation mode, and activate the Plane view.
The Plane view presents the echo data in a horizontal sector ("fan"). The sector direction can be changed in both vertical and horizontal directions. The tilt is drawn in the Vertical and Horizontal views as two dotted lines. The same dotted lines are shown in the Horizontal view as a dedicated bearing line to visualize the direction of the plane beam.
•  You can change the bearing on the Main menu. You can also click on the dedicated dotted bearing line in a Horizontal view and drag it.
•  You can change the tilt angle by means of the Tilt function on the Main menu.
The Horizontal Tx Sector function defines the opening angle of the sector.
•  The selected range is divided into identical distances.
•  The distance and depth of the cursor's location is shown in the lower right corner of the view.
•  The current settings for range, gain and tilt are show in the lower left corner of the view.
Tip
To fully understand how the beams behave in this view, use the Beam Visualization dialog box.
6 At the bottom of the display presentation, select a suitable presentation mode, and activate the Inspection view.
The SN90 system offers several inspection beams. Each inspection beam is presented using an Inspection view. The opening angle of the inspection beams depend on the operating frequency. The functionality offered by the inspection beams permits you to investigate chosen targets in more detail. In the SN90 system we use the phrase echogram to describe the information provided by the views.
Each Inspection view shows you echo data from a separate beam. If you use several Inspection views, you can train and tilt the beams individually, and independent of the beams displayed in the other views. You can select the start range (the depth from which the view starts) and the range (the “length" of the transmitted beam) by means of the Start Range and Range settings.
•  Small labels are shown in the bottom left and right corners of the view. These labels show you the time in order to identify the scale of the horizontal axis.
•  When enabled, equidistant horizontal scale lines are drawn in the view to indicate the range.
•  The Horizontal Scroll function controls how fast the echoes shall travel across the Inspection views.
Tip
To fully understand how the beams behave in this view, use the Beam Visualization dialog box.