Virtual variable applications

Acoustic data types

And, Or, Not operators.
Bitmap operators for data, regions, lines. Mask operator supports single beam, multibeam, linear and Unspecified dB. See also Masking with lines.

Acoustic data types
Some time series.

Allows you to apply a Python® script from a *.py file to specified operands to output an acoustic variable. See also Code examples.

Acoustic and time series data types

Allows you to apply a Python® script from a *.py file to an acoustic operand and any additional time series operands to output a virtual time series variable. See also Using the Code* operators.

Acoustic data types

Mathematical editor to create equations on a per sample basis. Takes multiple operands.

Acoustic data types

Create data pings with a specified value.

Limited acoustic data types

Resample by fixed distance interval.

Limited acoustic data types

Resample by number of pings.

Limited acoustic data types

Resample by a fixed time interval.

Multibeam

Resample by a fixed number of beams and data points.

Acoustic data types

Creates variable with a subset of pings from the operand. Good for decreasing calculation times and looking at specific features.

Acoustic data types

Applies the line and bad data exclusion settings specified on the Analysis page of the Variable Properties dialog for its input variable, changing excluded data points to "no data" values.

Acoustic data types

Creates variable with a subset of pings from the operand and transect. Good for decreasing calculation times and looking at specific features, while working with transects.

Limited acoustic data types

Applies a 2D convolution kernel to single beam data. Specify kernel size and select from Top hat, Guassian blur (weak, moderate, strong).

Multibeam

Applies a 3D convolution kernel to multibeam data. Specify kernel size, ping extent and select from Top hat, Guassian blur (weak, moderate, strong).

Limited acoustic data types

Enables you to resample Operand 1 to the exact ping geometry (start range, stop range, number of data points) of Operand 2. See also Handling blank echograms.

Acoustic data types

Selects pings from the first operand in such a way as to match the times of the pings in the second operand. See also Handling blank echograms.

Cell Statistic

Limited acoustic data types

Outputs a variable where a cell's sample values are set to a nominated cell statistic calculated from the input operand. Statistics include Mean, Minimum, Maximum, Median, Percentile, Number of samples, Beam volume sum, Echo density.

Cell Statistic - Single targets

Single targets
Limited acoustic data types

Outputs a variable with samples based on a statistic calculated from each cell. Operand 1 is single target data. Operand 2 is used to provide the geometry for the output ping, but note that ping times must still match.
Statistics include Mean, Minimum, Maximum, Median, Percentile, Number of samples, Beam volume sum, Echo density.

Interval analysis

Limited acoustic data types

Calculates an analysis variable per specified interval. Analysis variables include: ABC, Aggregation index, Area backscatter strength, Beam volume sum, Center of mass, Equivalent area, Inertia, Kurtosis, Exclude above line depth mean, Exclude below line depth mean, NASC, Proportion occupied, Skewness, Standard deviation, Sv maximum, Sv mean, Sv minimum, Thickness mean

Interval analysis - Single targets

Single target

Calculates an analysis variable per specified interval. Analysis variables include:Beam volume sum, Target count, Target depth mean, Target length mean, Target range mean, Thickness mean, TS maximum, TS mean, TS minimum, Wedge volume sampled

Interval analysis - Calibration

Acoustic data types

Outputs a time series of values - one measurement per ping. Values are for a selected calibration name from a list.

Interval analysis - Bottom feature

Limited Sv data types

Outputs a times series of bottom classification feature values for a specified interval of pings. Bottom features include: Bottom hardness normalized, Bottom kurtosis, Bottom line depth mean, Bottom maximum Sv, Bottom rise time normalized, Bottom roughness normalized, Bottom skewness, First bottom length normalized, Second bottom length normalized. The classification algorithms rely suitable first and second bottom echo data. See also Bottom classification - Notes.

Maximum intensity

Limited multibeam data types

Outputs a maximum intensity (single beam) echogram from multibeam data, where each sample (at range R) contains the maximum value of all the corresponding multibeam samples that are at range R. This provides a quick overview of strong returns in multibeam pings. The Maximum intensity - matrix operator does a similar thing for matrix data.

XxY Statistic

Limited single beam data types, including boolean

Applies a convolution filter statistic to the single beam operand. You can specify window size, and statistics include Mean, Minimum, Maximum, Median, Percentile, Standard deviation, Variance, Mean absolute deviation, Coefficient of variation, and Kurtosis. This operator may be useful for edge detection, intermittent noise removal, and other signal processing tasks, and can support more nuanced masking or preprocessing of data before the detection of single beam schools or targets.

XxYxZ Statistic

Limited multibeam data types, including boolean

Applies a convolution filter statistic to the multibeam operand. You can specify window size, and statistics include Mean, Minimum, Maximum, Median, Percentile, Standard deviation, Variance, Mean absolute deviation, Coefficient of variation, and Kurtosis. This operator may be useful for edge detection, intermittent noise removal, and other signal processing tasks, and can support more nuanced masking or preprocessing of data before the detection of multibeam schools or targets.