About single target depths

Echoview has two distinct analysis variables describing the depth of single target detections (there are many other depth related analysis variables in Echoview, see About analysis variables). The two variables and how they are used in Echoview is described in the table and diagrams below.

Analysis variable




The range of the target converted to depth along the beam axis. Target_on_axis_depth does not take the position of a single target within the beam into account.

  • Positioning of single targets on echograms.

  • Exported as the analysis variable Target_on_axis_depth.


The depth of the target at the position in the beam where the target was detected. Target_true_depth can only be calculated when angular position data are available.

Exported as the analysis variable Target_true_depth.

Note: When the required angular position data are not available, the Target_on_axis_depth value is exported.

See also

About depth, range and altitude
About single target ranges

About analysis variables

About mapping and map projections: Target depth