Target length frequency distribution

The frequency distribution of the target length (cm) of single targets within a region on a target length echogram can be exported to a .csv file.

Export settings

TS range and number of bins

You set the range of target length values that will be included in the analysis and the number of bins into which this range is divided using the settings in the Frequency Distribution section on the Graph page of the Variable Properties dialog box.

Hint: You can graph the frequency distribution prior to exporting to visualize the binning and target information that will be exported.

Data exported for each bin

You can export either the number of targets in a bin and/or the TS mean of targets in a bin. The export file contains a column for each single target frequency distribution analysis variable and a column for each target strength bin. The column for each bin can contain either the number of targets in a bin and/or the TS mean of targets in a bin.

You select which values to export on the Export page of the EV File Properties dialog box).

To export...	In the Export these analysis variables box, select...
the number of targets in each bin	Bin_count
the mean target length value of targets in each bin	Bin_TS_mean

If you select one option, the exported file will contain a single line for each domain that is analyzed. If you select both options, the exported file will contain two rows (one after the other) for each domain that is analyzed.

To export a TS Target distribution for a region (a defined region or fish track region):

On an active target conversion or target length calculator variable select a region.
Use the Shortcut (right click) menu and select Export Region, Target TS Distribution.

The first line of the .csv file lists the variables that are exported (these will be used as column headings if the file is loaded into a spreadsheet program). Each subsequent line contains the exported data.

(Target) Length frequency distribution file format (*.csv)

The following data are exported.

Variable	Description
Region_ID	Unique Region ID assigned to the region.
Region_name	Name assigned to region. Empty if export of a selection
Region_Class	Class of exported region. Empty if export of a selection
Process_ID	Unique Process_ID value for the export.
Attribute	Attribute that follows for each bin, either Bin_Count or Bin_TS_mean selected under Frequency distribution on the Export page of the EV File Properties dialog box.
Targets_Binned	See About analysis variables for descriptions. Notes: Region_bottom_altitude_min, Region_bottom_altitude_max, Region_bottom_altitude_min, Region_top_altitude_min, Region_top_altitude_max, Region_top_altitude_mean are automatically output under new EV files. Optional Frequency Distribution variables Bin_TS_count and Bin_TS_mean can be included with the export and may be specified on the Export page of the EV File Properties dialog box.
Targets_Failed_Thresholds
Targets_Failed_Filter
Targets_Excluded
Targets_Missed_Bins
Region_bottom_altitude_min
Region_bottom_altitude_max
Region_bottom_altitude_mean
Region_top_altitude_min
Region_top_altitude_max
Region_top_altitude_mean
Bin1 midpoint BinN midpoint	The first line then has the median Target length value for each bin from the first to last bin Binning is determined by the Frequency distribution settings on the Analysis page of the Variable Properties dialog box

Example file

Widen the brower window to view unwrapped field rows and exported results.

Region_ID,Region_name,Region_class,Process_ID,Attribute,Targets_Binned,Targets_Failed_Thresholds,Targets_Failed_Filter,Targets_Excluded,Targets_Missed_Bins,Region_bottom_altitude_min,Region_bottom_altitude_max,Region_bottom_altitude_mean,Region_top_altitude_min,Region_top_altitude_max,Region_top_altitude_mean,-46.25,-38.75,-31.25,-23.75
57,"Region 57","Small region",4326,Bin_count ,60,0,0,0,0,38.988512,39.312884,39.132643,70.753799,71.078171,70.89793,5,15,37,3
57,"Region 57","Small region",4326,Bin_TS_mean,60,0,0,0,0,38.988512,39.312884,39.132643,70.753799,71.078171,70.89793,-46.448178,-37.359001,-31.121822,-24.718325

Under this export from a target length calculator virtual variable, the absolute values of Bin_TS_mean are target lengths 46.448178 cm, 37.359001 cm, 31.121822 cm and 24.718325 cm.

Tip: It is possible to view a graph of the frequency distribution prior to exporting.