Exporting to the Echoview Data File Format (.evd)

Echoview Data File Format files (.evd) are created by Echoview when you export data. Exported files may be added to a fileset. Echoview derives variables from EVD files, this means that exported virtual variable data is cut off from the operator (and virtual chain). This can benefit workflow time for an optimally tuned virtual variable from a virtual chain. Echoview can also export a subset of pings to the Echoview Data File Format, based on measurement range and/or time range.

Export to Echoview Data File Format is available for:

  • Single beam - Power, Sv, TS, Unspecified dB, Boolean, Single target and Angular position variables
  • Multibeam - Sv, TS, Unspecified dB, Magnitude, Boolean and Angular position variables
  • Heading, Pitch, Roll, Length, (GPS) Position, (Vessel log) Distance and Line variables
  • Wideband and Pulse compressed Simrad EK80 SV, TS, Unspecified dB and Angular position variables

To export from an echogram

Single beam

  1. Display a single beam variable of data type Power/unspecified dB/Sv/TS/Angular position/Single target/Boolean.
  2. Under the Echogram menu, select Export, To Echoview Data File Format...
  3. On the export dialog box, select the variables to export and specify the Export options.
  4. Click Export...

Multibeam

  1. Display a multibeam variable of data type Multibeam unspecified dB/Sv/TS/Multibeam angular position/Multibeam boolean.
  2. Under the Echogram menu, select Export, To Echoview Data File Format...
  3. On the export dialog box, select the variables to export and specify the Export options.
  4. Click Export...

To export from the Dataflow window

  1. On the Dataflow window select a supported variable.
  2. On the Shortcut menu (right-click), select Export, To Echoview Data File Format...
  3. On the export dialog box, select the variables to export and specify the Export options.
  4. Click Export...

To export from Table, Graph or Cruise Track views

Cancel export

An Export to EVD File Format dialog box with a progress bar and a Cancel export button is displayed for an EVD export.

Notes:

  • The export is automatically canceled if the variable changes during export. Such a change could be an ECS file update.
  • A canceled export will delete only the last created file. This affects a multiple file export.

Export behavior

Exported data

Is stored in the EVD file

EVD file is added to a fileset, the information appears in Echoview under

AbsorptionCoefficient

Calibration element, AbsorptionCoefficient attribute.

  • When AbsorptionCoefficient is read from a data file or an ECS file, the value is exported.
  • When AbsorptionCoefficient is not read from file and all the parameters to calculate it are present, the calculated value is exported.
  • When AbsorptionCoefficient is not read from file and the parameters for its calculation are not available, a default value is exported.
AbsorptionCoefficient on the Calibration page of the Variable Properties dialog box.

CalibrationOffset

BeamOffsets

Calibration element: Attributes CalibrationOffsetSv or CalibrationOffsetTs or CalibrationOffset.

Variables derived from some file formats may use the calibration setting CalibrationOffset. When such variables are exported, Echoview tries to assign the CalibrationOffset value to the most appropriate of CalibrationOffsetSv or CalibrationOffsetTs (with respect to data type of the variable).

Multibeam variables may use CalibrationOffset and/or BeamOffsets.

Note: When there is a mismatch between the number of beams and the number of BeamOffsets, Echoview outputs all BeamOffset values as 0.0

Calibration page

Single beam variables: CalibrationOffsetSv or CalibrationOffsetTs or CalibrationOffset.

Multibeam variables: CalibrationOffset, BeamOffsets.

GPS position data

Packet element, Type="Position" attribute.

GPS position variable.

Export precision limitations on GPS data mean that distances calculated using exported GPS data will be slightly different from distances calculated with original GPS data.

Ping (from file)
Major-axis steered angle

Minor-axis steering angle

PingData element: Attributes MajorAxisSteeredAngle and MinorAxisSteeredAngle

Single beam variable, Details dialog box: Ping (from file).

Note: The steered angle from the first ping is exported with single beam data.

Multibeam calibration

Calibration element.

Notes:

  • The export of multibeam calibration settings includes SoundSpeed and AbsorptionCoefficient (for completeness only).
  • The multibeam data export is functionally restricted to SoundSpeed, sample value and sample range/depth.
SoundSpeed is applied to variables derived from the EVD file. Other calibration settings are not applied. The AbsorptionCoefficient may be used by operators.

(GPS) fix status - None

Status attribute of the Parameters element for the Position Packet.

The export uses "None" when it is present in GPS data. However, when the EVD file is added to an EV file "None" is processed as "Bad".

EVD files created outside of Echoview, may use "None" as a GPS fix status.

GPS position variable, GPS fix status.

Refer to:

EffectivePulseDuration
PulseCompressedEffectivePulseDuration

Calibration element.

EffectivePulseDuration and PulseCompressedEffectivePulseDuration will be written to the EVD file if they've been specified.

EffectivePulseDuration or PulseCompressedEffectivePulseDuration will replace the TransmittedPulseDuration in the general Sv and TS equations. However, range calculations will continue to use TransmittedPulseDuration.

Transducer - additional information

Transducer element: attribute list.

Echoview exports Sounder="SubstituteInYourSounderName"

Notes:

  • A Sounder value may not be accurate for variables from two different systems with the same Parameters element Transducer attribute value.

Transducer attribute list information appears under Ping (from file) on the Details dialog box.

TvgRangeCorrection

TvgRangeCorrection is not exported to the EVD file.

TvgRangeCorrection is set to Standard for single beam variables.

Variable

Parameters element, Transducer, Channel and Source attributes

Notes:

  • When two raw variables have the same data type, transducer and channel, the second variable is exported with a different channel number.
  • Virtual variables will be assigned a new channel number if there is another variable included in the export which shares the data type, transducer and channel.
  • When there is no frequency information, Echoview is unable to create variables based on frequency.

Transducer number and Channel number are incorporated into the derived variable name.

The Parameters element Source attribute value is displayed on the Details dialog box under Ping (from file).

Variable name

Parameters element, Source attribute

The original variable name is displayed under the Details dialog box - Ping(from file).

CtdDepthProfile

SoundSpeedProfile

Calibration element, CtdDepthProfile and SoundSpeedProfile attributes.

Note: The EVD export of variables that use of CtdDepthProfile and SoundSpeedProfile, in effect outputs resampled echogram data. This means the original echogram data where the sound speed is constant can't be recalculated.

CtdDepthProfile and SoundSpeedProfile under the Calibration page of the Variable Properties dialog box.

Notes:

  • The Echoview Data File Format exports the calibration settings that are read from the fileset data file(s), as well as settings that are set by a specified ECS file and calibration settings that are specific to the data file format.
  • Exclusion lines or Exclusion surfaces specified on the Analysis page of the Variable Properties dialog box are applied to the export data.
  • Exported calibration value precision is as used in Echoview. See also Calibration Information dialog box - No EV file, default display.
  • EVD file size and performance are dependent on the original file format, data type, specified exclusion lines, specified data compression quality and the number of variables exported. EVD files with multibeam variables may be very large.
  • EVD underlying data export note.
  • Special export values in EVD files are read correctly when the EVD files are added to a fileset.
  • Simrad Ex60 Note.
  • Simrad EK80 Note.
  • Simrad ME70 Note.
  • Sonic Note.

Echoview Data File Format (.evd)

An .evd file consists of XML and binary data that can be read by Echoview. The inclusion of binary data means that the EVD file is not a pure XML file, and therefore may not display correctly in a typical XML file viewing application. We recommend Echocheck be used to assess the validity of .evd files.

File structure

An EVD file is structured as a series of XML elements, each of which are described in the Echoview Data File Format document. The elements are written as ANSI text. Each element consists of an identifying Tag, and Attributes which are written as AttributeName="Value" pairs, where the Value is enclosed by quote marks.

Example

<Packet Type="SinglebeamPing">

The tag is Packet. There is a one attribute called Type which has the value of SinglebeamPing.

Binary data

Certain elements of the file will contain binary data, which are written as little-endian values for Echoview to read them correctly.

See also

Export file formats
About the Echoview Data File Format
Echoview Data File Format files
Scripting support - export from a variable
Scripting support - export from a virtual variable