About variables

An Echoview "variable" is a time-series of measurements of one data type. Echoview uses variables to organize source data (e.g. data files from an echosounder) for display, analysis, export, etc. purposes.

Variables are represented on the Dataflow window and in the Raw variables section of the Filesets window.

Example:

A data file from an echosounder may contain the transmitted and received properties of acoustic pulses (pings), and the geographic position of a ship at the time each ping was transmitted. Echoview would derive one or more acoustic variables from this data file (an Sv variable, TS variable, a single target variable, etc.) and a position variable e.g. (the GPS fix for each ping). The acoustic variables can then be displayed as echograms, analyzed, exported etc. The position variable can be displayed as a cruise track.

Raw variables, virtual variables and editable variables

Variables are divided into these categories:

Variable category

Description

Raw variable

Variables that are derived directly from data stored in data files.

Virtual variable

Variables that are created from other variables using operators (mathematical algorithms).

Editable variable

Variables whose values are stored in the EV file and can be edited. Editable variables include Editable lines and Bottom points variables.

Variable names

Each variable in Echoview has a name.

Variable classes

Variables are divided into the following classes.

Variable class

Description

Acoustic variable

Variables that contain a time-series of measurements associated with the transmitted and received properties of ping.

 

Note: The data type of an acoustic variable may not be same as the data type stored in a data file, e.g. a data file may contain voltage measurement from which Echoview derives Sv values to create an Sv variable.

Attitude variable

Variables that contain a time series of measurements associated with the heading, roll, pitch and yaw of a platform.

 

Note: Only heading, roll and pitch variables are currently supported.

Distance variable

Variables that contain a time-series of measurements associated with distance traveled by a platform from an arbitrary zero point.

 

Note: Only vessel log variables are currently supported.

Line variable

Line variables are composed of a series of time/depth co-ordinates (or time/range co-ordinates for sounder-detected bottom raw lines).

Line variable data types include: raw line, editable line and virtual line.

See About lines for more information.

Geopoint variable

Variables that contain a time-series of geopoint records. A geopoint record consists of latitude, longitude, altitude and measurements.

 

Note: Only bottom points variables are currently supported.

Position variable

Variables that contain a time-series of measurements associated with geographic location of a platform.

 

Note: Position variables and heave variables are currently supported.

Media variable

Variables that contain a time-series of image or video data.

See also

About raw variables
About virtual variables

About the Dataflow window

Data types