BlueView data files

The BlueView *.son file format is supported in Echoview. BlueView imaging sonars produce several high quality images per second, making it possible to view movie-like imagery.

Echoview supports *.son files output by the BlueView ProViewer software using BlueView SDK version 4.5 and version 4.6 from products including the M450 and M900 series sonars.

The version of the SDK Echoview is using is displayed in the File section of the Details dialog box. Data is displayed in a multibeam echogram where images correspond to pings.

Sample and beam data and Transducer type are read, as well as the following data if available:

  • Head name, Head number, Fluid type, Sound speed, Minimum range, Maximum range, Gain adjustment, TVG slope, Center frequency, GPS, heading, pitch and roll.

The absorption coefficient is not available in the data file but may be required by the derived Sv frames variable. Echoview applies a default absorption coefficient of 1.0 dB/m for Sv frames variables; which appears to be satisfactory for common single transducer head systems. Be aware that multiple transducer head systems have a default absorption coefficient applied to first head data that may be suitable but the default value applied to second head data may be unsuitable. If you can determine the frequency used by the heads, it is possible to calculate and specify more suitable absorption coefficients. The value for AbsorptionCoefficient may be specified with an ECS file. The Sonar calculator offers an absorption coefficient equation that considers temperature, speed of sound, frequency, salinity and depth.

The underlying sample data to unspecified sample data (dB) calculation is:

-9999 for zero
Unspecified sample data (dB) = 2 x 10 log 10 (Sample data)


  • Warning messages that include "BlueView error" indicate that BlueView's proprietary file handling code has output an error. Please contact BlueView Technologies for assistance with such files.
  • The sound speed read from the *.son file is used but the data is adjusted to the calibrated sound speed, which defaults to 1500.
  • A message is displayed when the BlueView file is unindexed. Unindexed files may have been saved incorrectly. You can index and re-save such files with BlueView software.
  • Echoview displays samples at polar image coordinates read from the BlueView file. The BlueView ProView software displays samples at cartesian image coordinates. This difference will result in a subtle variation when directly comparing the visualization of neighboring samples between products.
  • An EVI file is automatically created (if it does not exist) and speeds up subsequent Echoview access to BlueView data. EVI creation time can be lengthy.
  • Large files may have long load times, especially if they are unindexed. Echoview has no control over the timeliness of data output from the proprietary BlueView SDK. For information about BlueView SDK algorithms contact BlueView Technologies.
  • As of SDK version 3.5, BlueView files are indexed. BlueView files that are indexed open more quickly than unindexed files. Unindexed files are indexed before the data is displayed in Echoview.
  • There is a known issue where some older BlueView files are incompatible with BlueView SDK version 4.0. When one of these files is loaded a message is sent to the Message dialog box advising that Echoview should be restarted. Please contact BlueView Technologies for assistance with updating such files.

See also

Calibration settings for BlueView data
Raw variables derived from BlueView data
Multibeam display note