How to open
An echogram is displayed for each channel view, however it is possible to toggle between different types of echograms.
To activate Surface echogram, click in the chosen view to make it "active". Select Echogram on the Active menu. In the Echogram dialog box set Echogram Type to Surface. The different echograms can be opened using the Echogram shortcut menu.
Shortcut menus
The different echograms can be opened using the Echogram shortcut menu. Right-click in the view to open the shortcut menu. The Echogram shortcut menu can be used to open the Echogram dialog box.
Description
The Surface echogram is often used to study the water column from a few meters under the hull and down to the bottom. If you set up the Start Range and Range depths to place the sea bottom contour at the lower end of the echogram, you will have good opportunity to study the echoes
from the water column. Since this echogram is referenced to the sea surface, the sea bottom contour will vary with the actual depth.
The biomass is automatically calculated based on choices you make in the Calculation Interval dialog box; within a given time frame, a defined number of pings, or a portion of the echogram view. The data is then taken from an echo area starting immediately after the transmit pulse, and ending just over the detected
depth.
If you have limited your vertical range (using the Start Range and Range settings), the resulting area is used for the biomass calculation. If the seabed is clearly defined with a unique bottom detection, the bottom echo will not be included in the calculations. Therefore, if you switch the bottom detector off, the bottom echo will be included in the calculation.
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A |
This is the start depth of the echogram In a Surface echogram you may wish to start the echogram from the surface, and will then set the Start Range to 0 (zero). You will then see the transmit pulse as a strong echo at the top of the echogram. Try setting Start Range to a small value, for example 1 meter. The echogram will then start immediately under the keel or transducer face.
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B |
This is the bottom (seabed) The bottom is shown with a strong contour. Since the echogram is referenced to the sea surface, the bottom will vary with
the actual depth. Different bottom conditions will have a visual effect on how the bottom echo is drawn. A hard bottom (rock) will give you
a stronger echo - and thus a darker colour - than a soft bottom (mud or silt).
The Echogram page in the Echogram dialog box allows you to make adjustments to the bottom contour. You can add a black bottom line, and a white line to make the bottom "stand out".
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C |
This is the lower end of the chosen depth range This depth is normally a few meters below the bottom contour, depending on the chosen range. The total echogram range (A) to (F) is defined with the Range button on the Main menu.
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At the bottom of the echogram beam number (MBES), operating frequency (kHz) and steering angle relative to the transducer
array (x, y) are displayed.
ExampleStart Range in a surface related echogram
In a surface echogram, set the Start Range value to 10 meters. This will make the echogram start from 10 meters below the sea surface (provided that the transducer
offset has been defined). Set Range to the current depth plus 20 meters. The echogram will now show the area from 10 meters below the sea surface, and down to
10 meters “below” the bottom. The bottom contour is easily detected when the depth changes.
Details
To activate a field and hence a channel, you must first click in the field. By doing so the menus and options available will
adjust to the activated field and also apply to the active channel for this field. In this context , the phrase channel is
used as a common term to identify the combination of transceiver, transducer and operating frequency.
You can easily change the physical size and shape of the fields. Click on the grey lines between the fields and drag to new
size. Note that this will cause one field to increase in size and another to decrease.
Right-click in the active field and select Hide View from the shortcut menu to close the field.
Right-click in any of the fields in the active channel and select Configure Window to be able to reopen a field.Select the field(s) you want to re-open by ticking of the name in the Show Views listClick on the Apply button for the field to appear