Analysis page

The settings and sections that are available on the Analysis page for a specific variable will depend on the data type. All possible sections and settings are described below.

Exclusions

The Analysis page may also be displayed for selected multiple variables (on the Dataflow window).

Single beam variables

The Exclusion section allows you to choose:

Notes:

Settings

Description

Exclude above

Select a line above which the sample data is excluded from analysis, export analysis and export data.

Note: This setting can be used by Echoview integram analysis and the integram detection feature.

Exclude below

Select a line below which the sample data is excluded from analysis, export analysis and export data.

Note: This setting can be used by Echoview integram analysis and the integram detection feature.

Multibeam variables

The Exclusion section allows you to choose:

Note: Exclude above and below surfaces work with respect to the transducer face.

Settings

Description

Exclude above

Select a surface above which the sample data is excluded from analysis, 3D School detection, multibeam surface detection, export analysis and export data.

You may want to view the intersection of the surface with the multibeam pings to check what will be excluded.

Exclude below

Select a surface below which the sample data is excluded from analysis, 3D School detection, multibeam surface detection, export analysis and export data.

You may want to view the intersection of the surface with the multibeam pings to check what will be excluded.

Bottom elimination for 3D schools detection

These settings are available for multibeam variables:

Settings

Description

Exclude below surface additional depth offset (m)

The Exclude below surface is offset by the specified depth (m).

Positive values will increase the effective surface depth used in 3D school detection. Negative values will decrease the effective surface depth.

Exclude data beyond the minimum range of the Exclude below surface.

Select this setting to exclude all samples beyond the range R, where R is the range to the nearest point (to the transducer) on the surface-ping intersection. This feature is intended to help remove the bottom echo trace sometimes visible in multibeam echograms beyond the range R (that may be an artifact introduced in the beam forming process). 

Analysis

(Integration) Analysis settings may affect integration calculations when Sv echograms contain no-data and/or bad data regions.

- OR -

(Single target) Analysis settings may affect analysis calculations when Single target echograms contain no-data and/or bad data regions.

Note: Analysis settings will affect Bottom classification and may result in a meaningless bottom classification. It is advised that Apply bad data regions and Include the volume of no-data samples are not used for variables configured for bottom classification.

For further information refer to:

The Analysis section settings include:

Settings

Description

Set pings with bad line status on the exclude below line to no-data

If selected, this option will exclude from analyses those samples or single targets in pings where the line status of the exclude-below line is bad.

Apply bad data regions

If selected, Echoview applies specific bad data region sample values and sample intervals.

For single target echograms, the range intervals that coincide with bad data regions are affected.

Apply bad data regions is the default setting for new EV files.

This setting is unsuitable for variables used for bottom classification.

See also: Examples of integration cues and outcomes.

Include the volume of no-data samples

- OR -

Include the volume of bad data (no-data) regions

Sv echograms

If selected, no-data samples have a sample interval.

If cleared, no-data samples are treated as if they have no sample interval. In this case the setting will affect primary and downstream integration calculations and bio-estimates.

For new EV files this setting is selected by default.

For EV files from previous Echoview versions, the selection of Include the volume of no-data samples is matched to the state of the historic settings in the Analysis section of the Analysis page of the Variable Properties dialog box.

This setting is unsuitable for variables used for bottom classification.

See also Whole excluded or no-data pings removed from ping count emulation discussion.

See also: Examples of integration cues and outcomes.

Single targets echogram

If Include the volume of bad data (no-data) regions is selected, range intervals that coincide with bad data (no-data) regions are included in analysis calculations.

If Include the volume of bad data (no-data) regions is clear, range intervals that coincide with bad data (no-data) regions are excluded in analysis calculations.

The Background noise setting can affect specific analysis variables and the Graph ping: Sv at 1 meter value.

Setting

Description

Background noise at 1m (dB)

Specify the background noise level that will be used in calculating background noise in an analysis domain.

Note: You can use the Ping graph Shortcut menu Sv TVG Curve, Sv at 1 meter (dB) to visually estimate this value for an Sv echogram.

Bottom

The Bottom settings section is used to specify key Bottom classification parameters for the Sv variable. Bottom classification algorithm parameters can be modified on the Bottom Classification page of the EV File Properties dialog box. Note that Analysis settings are unsuitable for bottom classification. For further information refer to About bottom classification.

Setting

Description

Bottom line

The bottom line used for bottom classification.

Bottom echo threshold at 1m (dB)

The threshold that determines the end of the first bottom echo and second bottom echo. See also: Bottom classification algorithms - Extent of the first and second bottom echoes.

Depth normalization reference depth (m)

Reference depth used for bottom classification depth normalization.

Frequency Distribution

The Frequency distribution section is used by single target variables.

Settings

Description

Minimum value

Analysis export frequency distribution parameters for the single target variable regions.

Note: These settings may be affected by the settings on the Graph page of the Variable Properties for a single target frequency distribution graph.

Maximum value

Number of bins

Link Acoustic Variable

The Link Acoustic Variable section is available for a position variables (i.e. position GPS fixes). Select a variable from the Linked acoustic variable list to be the source of data for the integration of regions on the cruise track window.

Note: The Along track window is by definition linked to an acoustic variable and therefore does not require the selection of an Linked acoustic variable.

Vegetation

The Vegetation section is available for an acoustic variable with an associated vegetation boundary line. The vegetation boundary line may be detected by the Threshold offset operator. Other line creation methods can also be used to create a vegetation boundary.

Note: Consider using a Minimum and/or Maximum threshold on the Data page for the analysis.

Setting

Description

Vegetation line

A selected line from the Vegetation line list. The line represents a vegetation boundary.

Bottom line

A selected line from the Bottom line list. The line represents a bottom boundary for the vegetation.

Time/ping interval

Specifies the vegetation analysis interval unit:

  • Time
  • Ping number

Time between intervals (minutes)

Specifies the time in minutes for the vegetation analysis interval.

See also

About analysis domains
Variable Properties dialog box
About integration
About samples and echo integration
About no data
Thickness mean and Height mean
ABC and NASC