About fish track detection
Fish track detection is used to identify groups of single targets (echoes) that show a pattern of systematic movement. The targets grouped into a fish track are assumed to have been generated by a single object moving through space.
Warning: Single targets are positioned on echograms using Target_on_axis_depth not Target_true_depth. The depth related calculation Fish_track_change_in_depth uses Target_true_depth (when available) otherwise Target_on_axis_depth is used. See About single target depths before interpreting depth related information. The fish tracking algorithm uses neither target_on_axis_depth nor target_true_depth and works entirely in range space.
- Compare with region tracking. Region tracking is intended to track schools of fish detected on multibeam data, and fish tracking is intended to track individual fish detected on single beam data.
- Restricted values can be reported by the fish track analysis variable Direction_vertical when the platform is moving and a position GPS fixes variable is absent.
- Several platform properties affect fish track analysis variables. A mobile platform with no GPS data leads to uncertainty in angles for fish tracks. Fixed platforms should use Heading source: Fixed heading (north) to establish an appropriate reference frame for fish track calculations. See also: Transducer geometry illustrated.
- About speed data
See also:
Detecting fish tracks
About fish track regions
Fish track editing
Track Detection Properties dialog box
About single target detection
Fish tracking algorithms
About single target depths
About single targets