1 Creating a new depth layer

Different species often occupy different depth layers. Such layers may be defined by salinity or temperature, or simply by ambient light or the availability of food. In order to study these species, the EK80 supports a Layer function. By means of this function, you can create your own depth layers in the water column to improve the dynamic data required for analysis. You can create as many depth layers as you want on the EK80.

Context

Layers are used to calculate various values from the echo data collected within a specific depth range in the water column.

By default, a background layer collects all the data from the range chosen on the Main menu. Unless you specify your own layer(s), all data presented by the various information panes are calculated from this background layer. However, with a large range selected - as in the background layer - the data will not be very accurate.

Once you create your own layer, all calculated values from this layer are displayed in the Numerical information pane. When the layer is selected ("activated") in the Numerical information pane (layer data shown with red text) or in the echogram, all data shown by the relevant information panes are calculated from the echo data within the selected layer.

Procedure

Open the Active menu.

Select New Layer.

Observe that the New Layer dialog box opens.

Select layer type.

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Surface: The range settings for the layer are referenced to the surface. The layer is downwards limited by the detected bottom depth if this value is shallower than the specified lower range limit for the layer. "Pings" without a bottom detection are ignored in the calculations.

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Pelagic: The range settings for the layer are referenced to the surface. The layer is not downwards limited by the detected bottom depth.

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Bottom: The range settings for the layer are referenced to the bottom. The layer is downwards limited by the detected bottom depth.

Define the start depth and the depth range of the layer.

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Start Relative Surface: When a Surface or Pelagic layer is chosen, this setting controls the depth at the upper boundary of the layer relative to the surface depth.

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Start Relative Bottom: When a Bottom layer is chosen, this setting controls the depth at the upper boundary of the layer relative to the bottom.

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Range: This parameter controls the vertical depth range for the layer. Positive values are always downwards. A start range relative to bottom of for example -10 m means 10 m above the bottom.

Set up the Integration parameters to match your requirements.

Select OK to save the selected settings and close the dialog box.

Result

When a layer is established, it is drawn with two horizontal lines in the echograms. The lines identify the upper and lower depth settings. If you have only one layer, it will always be "active", and shown with red lines. If you have more than two layers, the "active" layer is shown with red lines, while the others are shown with black lines.

Further requirements

By default, any layer you create will be applied to all echogram views simultaneously.

In the echogram, you can click between the layer lines in the echogram view to select ("activate") it. The active layer is shown with red border lines. The information shown in your information panes only reflect the echo data from the currently "active" layer.

The Numerical information pane is the best tool for controlling your depth layers. All layers are listed, even those that may be located outside your current echogram presentation. The different layers can easily be activated by clicking the list of numerical data.