About heave data
Heave data are records of the vertical motion of the platform. Echoview can read heave data (see note) and generate a heave line that is a time series of depths. In Echoview, a positive heave value (from the heave line) represents downward motion. The heave at any time along the heave line is calculated by interpolating between the two nearest adjacent line points.
- The recorded direction for positive heave in the primary heave data may be different from the depths in the generated Echoview heave line.
- Echoview can use GPGGA NMEA strings containing GPS information to generate a position variable and a heave line.
What is affected by heave data?
A platform may be affected by heave or other vertical motions while echosounder data is logged. Echogram samples may not be displayed at the correct depths when heave is present but is not accounted for. As a result this may affect analyses of echogram data.
Heave compensation can be applied by selecting a line as the Heave source on the Platform Properties dialog box, Position tab. For more information refer to About heave compensation.
See also
Platform Properties dialog box
About transducer geometry
About depth, range and altitude
About lines
Line graph: Heave
About heave compensation
Heave analysis variables