Term
Definition
Sometimes called beam width, and in early versions of Echoview nominal angle.
For a single acoustic beam, the angle between the half power points of the main lobe of the transducer beam pattern measured in degrees. If the beam is elliptical the 3dB beam angle is measured separately along the major and minor axes.
Multibeam echosounders produce many individual acoustic beams each with a 3dB beam angle or two (minor and major axis).
In Echoview, the 3 dB beam angle is defined independently for the minor axis and major axis on the Calibration page of the Transducer Properties dialog box. For circular transducers the major and minor axis 3dB beam angles are equal.
See: About calibration settings for more information.
The 3dB beam angle along the minor-axis.
The 3dB beam angle along the major-axis.
A group of 3D regions intended to show a pattern of systematic movement for detected schools. A 3D region track is a specific variant of the 3D polyline.
See: About 3D region tracks for more information.
A group of 3D region tracks intended to capture the results of a single region track detection.
A point in three dimensional space, having latitude, longitude and depth. A 3D point will generally also have a valid time and sometimes an intensity. This is not a 3D object in Echoview but a part of other 3D objects.
Viewed on a scene, 3D points can be seen as spheres in a 3D region track, 3D polyline, 3D single targets object or 3D fish tracks object and as vertices in any other type 3D object for example.
A group of 3D polylines resulting from a single import of 3D polylines.
Area backscattering coefficient.
See: ABC and NASC for more information.
Absorption coefficient of sound in water in dB per unit distance (dB/m).
See: About calibration settings for more information.
Acoustic variable
Variables that contain a time-series of measurements associated with the transmitted and received properties of pings.
See: About variables for more information.
The finish of the acquired time range for a 3D object.
The start of the acquired time range for a 3D object.
A property of 3D objects which defines the time over which the data for this object was acquired. An object may have a single acquired time (for a multibeam ping curtain for example. The acquired time for a group would be the time period covering all of its component objects.
The acquired time is seen on the Time page of the (3D Object) Properties dialog box.
Active window
The active window will have it's title bar highlighted and will receive keyboard commands.
An equirectangular projection in which the standard parallel is chosen individually for each object that is mapped, at the centroid of that object. As a result each object mapped experiences minimal distortion but when multiple objects are mapped they do not experience the same distortion. This is especially pertinent when multiple objects are added to scenes in Echoview.
Acoustic Doppler Current Profiler - a device using sonar data (in particular the frequency shift caused by the Doppler effect due to relative motion between transmitter and receiver) to measure water current velocities.
A calibration setting used on HTI echosounders. It is typically stored in HTI data files, but for some early versions of HTI data files it is not present. Specifically version 0.0 .INT files which Echoview supports, are lacking this constant and you will need to calculate it and enter it on the Calibration page of the Variable Properties dialog box. This setting will not be present on the Variable Properties dialog box for versions of HTI data files which contain the constant.
The direction on ship which runs from bow to stern. Typically Simrad transducers have an alongship axis which is the equivalent of Echoview's minor-axis. Simrad may also refer to this axis as the 'longitudinal' axis.
Synonym for absorption coefficient.
The colored fill pattern that is displayed in an analysis domain when you complete an on-screen integration or an on-screen analysis of the analysis domain on an echogram.
Hint: You can choose the analysis-hatching color for custom color schemes. To set the analysis-hatching color for a custom color scheme: open the color scheme in Echocolor; display the Miscellaneous page of the Palette Properties dialog box; and select the required color in the Analysis-hatching color box.
Data logged by an echosounder which attempts to predict the angular position of targets within the beam. Only returned by split-beam echosounders, these data are based upon differences in signal phase measured at different points on the transducer phase - from which the direction of an arriving wavefront is estimated. Very useful when working with single targets, angle data are all the same, generally less reliable than range measurements for the purposes of spatial measurements.
The direction on ship which runs from port to starboard. Typically Simrad transducers have an athwartship axis which is the equivalent of Echoview's major-axis. Simrad may also refer to this axis as the 'Transversal' axis.
Variables that contain a time series of measurements associated with the heading, roll, pitch, yaw and heave of a platform.
Note: Only heading and roll variables are currently supported.
See: About variables for more information.
A feature that is available to automatically maintain the display of the same, or nearest, time on echogram windows.
See: Auto-synchronization of echograms for further information.
Azimuth is the angle between the beam axis and the stern-bow (or south-north) axis.
See: About beam geometry and About transducer geometry for further information.
Scattered by a target back in the direction of the acoustic source.
A measure of the backscatter strength from the target, denoted by sbs.
Backscattering cross-section in m2 is defined* by:
Where:
Iinc is the intensity of the transmitted or incident wave at the target.
Ibs(r) is the intensity of the backscattered wave at a distance (r, -p, 0) from the target.
r is the distance (m) of the measurement position from a small target (whose size is less than the radius of the first Fresnel zone).
a is the acoustic absorption coefficient (dBm-1).
A useful relationship is that of:
where TS is the measured target strength of the target.
*MacLennan et al 2002 Table 1.
Background noise is the signal present at the output of the echosounder receiver when the transmitter is turned off. Background noise is also present when the echosounder is transmitting. Correction of the echo integral for background noise may be necessary where the signal to noise ratio is low.
See: Use of background noise in Echoview for more information.
Sv_noise, NASC_noise, ABC_noise.
Data that falls within a bad data region.
A region containing data points to be excluded from all analyses. See Region type and About analysis domains for further information.
On Simrad Ex500 series echosounders a setting of this name can take the value of Narrow, Wide, or Auto which must be specified on the Calibration page of Variable properties dialog box for the Power to Sv or TS calculation. Note: This setting is not required for data from a Simrad Ex60 series echosounder. See also Pulse length.
A file that contains a sequence, or batch, of commands. Batch files are useful for storing sets of commands that are always executed together because you can simply enter the name of the batch file instead of entering each command individually. See your Windows help for information on creating batch files.
Bathymetric data extraction
The process of obtaining bathymetric data (bottom picks) from echogram data in Echoview.
See: Export file formats for more information.
A constituent part of a multibeam ping.
See: About sector plots and beams and About pings
The axis at the center of the acoustic beam. For single beam echosounders this is the same as the transducer axis. For multibeam echosounders each beam has its own axis.
See: About beam geometry and About sector plots and beams for more details.
Position measured along the beam-axis. This is identical to range for targets on the beam-axis, but for targets not on the beam-axis it will typically be shorter than the range.
See: About single target ranges for more information.
The compensation applied to a measured TS value correcting it for transducer directivity, that is for the location of the target within the transducer beam pattern.
See: Beam compensation for an overview of beam compensation methods used in Echoview.
The number of a particular beam in a multibeam acoustic variable (0 to n-1, where n = the number of beams).
A value in degrees that describes the width of the swath produced by the transducer lens. Beam spread for a DIDSON standard lens is 29 degrees or 14.4 degrees for a DIDSON big lens and is deduced from the data file header.
The value for beam spread will affect the sector angle displayed on the sector plot.
A synonym for 3dB beam angle. Called the nominal angle in early versions of Echoview.
Beam width, displayed
See Displayed beam width.
A term used for scanning sonar systems to describe the angle of clockwise vertical rotation of a beam fan. Bearing angles range from 0 to 360 degrees. Zero bearing is defined in an instrument specific manner. See your echosounder details for further information. Bearing applies to V-mode and S-mode beams only.
The mass of living organisms such as plankton or fish. Biomass can be calculated from acoustic backscattering strength (Sv) and target strength (TS) data combined with other information. The conversion of Sv or sA to biomass is covered in the basic texts on fisheries acoustics, see the References topic for a specific text.
An obsolete term from version 1 meaning a region defined by a pair of lines and depth offsets from those lines.
See: About lines for more information.
Bottom detection
See: Bottom pick
Bottom detection algorithm
An algorithm used in the automatic selection of a bottom pick for a ping or sequence of pings.
See: Line picking algorithm for more information.
The echo trace attributed to the sea bed.
See: Echo trace
The depth of the seabed below the transceiver or alternatively if a draft has been set for the transceiver (i.e. transceiver depth) then it is the depth below the sea surface.
See: Line picking for more information.
A message sent to all computers on a subnet. It is usually addressed to a particular UDP port. The message will be ignored by individual computers unless they have a program running which is currently listening for messages on that port.
A value which describes the behavior of an echosounder or of the environment in which it is operating, for example the operating frequency of the echosounder or the speed of sound in water.
A value in decibels added to each data value.
See: Using Echoview in the calibration process or Choosing a calibration offset for Sv to TS and TS to Sv conversion for ways in which to determine the value you need to apply.
Cell Depth - A superceded analysis variable from pre 3.00 versions. Superceded by Range_mean and Depth_mean.
Cell integration
Integration of a data in cells where cell boundaries are defined by a grid.
See: Integrating cells for more information.
Depending upon the context this may refer to the central transducer axis or the central beam axis. For single beam echosounders they are the same, for multibeam echosounders these differ.
The position of the point at the mass center of an object - that is the point at which the mass of the object can be assumed, for many purposes, to be concentrated. This is a property of mass distribution within an object, the calculation of which requires access to Sv data for the space within the object - compare with Geometric center and Centroid.
Typically used to describe the center of mass or the geometric center. Because of this ambiguity the term is avoided in Echoview in favor of the less ambiguous center of mass and geometric center.
A superceded analysis variable from pre 3.00 versions. Superceded by Fish_track_change_in_range and Fish_track_change_in_depth.
Cell Height - A superceded analysis variable from pre 3.00 versions. Superceded by Thickness_mean and Height_mean.
A global electronic chart service. See http://www.c-map.com/
C-MAP charts and C-MAP surfaces were supported in Echoview versions 3.30 to 4.30. C-MAP support was removed in Echoview 4.40.
The sum of Color display minimum and Color display range.
A setting on the Display page of the Variable Properties dialog box which defines the data value which is mapped to the minimum color in the selected color scheme. This influences only the display of data and not the analysis of data. This is distinct from the Minimum threshold on the Data page of the Variable Properties dialog box which does influence the analysis of data. The Minimum threshold can be linked to the color display minimum on that page however, in which case altering the color display minimum will alter the minimum threshold also which will affect analyses.
A setting on the Display page of the Variable Properties dialog box which defines the range data values which is mapped to the selected color scheme. This influences only the display of data and not the analysis of data.
The maximum data value mapped to the color scheme is termed the Color display maximum and it is equal to the Color display minimum plus the Color display range. This is distinct from the Maximum threshold on the Data page of the Variable Properties dialog box which influences the analysis of data. The Maximum threshold can be linked to the color display maximum on that page however, in which case altering the color display range or the color display minimum will alter the maximum threshold also which will affect analyses.
Color legend
A legend relating the color of pixels on the echogram display to volume backscattering strength (dB re 1m-1). See Color legend dialog.
Target strength derived from received power signals with beam compensation applied. This is available in the analysis variable TS_comp.
See also: Uncompensated_TS
Schools analysis variables that are only available for export if the schools detection module is licensed.
See: Schools Algorithms for more information.
The path of a ship or vessel over the water surface.
See: Using Cruise tracks for more information.
Comma-separated values files - an ASCII file format in which each complete value (e.g. a data value, name of an analysis variable) is separated by comma. The first line of a CSV file typically contains 'column headings' and each subsequent line contains the data values. The majority of exports in Echoview are written to CSV files.
See: About file formats, Export file formats for more information.
Note: Echoview will allow you to add CSV data files to a fileset if they meet certain criteria (see ASCII data files).
The projection of an echogram into a 3D scene allowing visualization of the relationships of echosounder pings to other 3D objects.
A self contained packet of information in a data file.
See also: Telegram, tuple.
A single Sv or other variable value on an echogram. A synonym for Sample.
See: About echograms for more information.
An area on an echogram where biomass within a beam is indistinguishable from the bottom echo (Kloser et al. 1996).
See: About the deadzone for more information.
Echoview supports the input of latitude and longitude in both decimal degree format and the degree and minute format.
See: About degrees and minutes for more information.
Bottom or near bottom living species.
Linear distance from the water surface along the vertical axis.
See: About Depth and Range Mode and About single target depths for more information.
A regular grid of lines of constant depth or range displayed on the echogram.
See: Grid page of the Variable properties dialog box for more information.
Dynamic Host Configuration Protocol server. DHCP servers allocate IP addresses dynamically so that addresses can be reused when hosts no longer need them.
Digital echogram data
Digital data that can be used to display an echogram.
The angular width, in degrees, of a beam as displayed on a multibeam sector plot.
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.
See: About variables for more information.
Dongle
A software protection device that attaches to the parallel or other port of a PC. Myriax uses HASP dongles for licensed users.
See: Dongle installation for more information.
The depth of the center of the transducer face relative to the water surface. In Echoview this is the difference between depth and range for a downward pointing vertically oriented transducer.
See: About draft for more information.
Draft correction was a calibration setting in older versions of Echoview. It was replaced by transducer geometry in Echoview 3.
See: About draft for more information.
A dynamic-link library (DLL) is a file which can have an extension .dll, that can be loaded and executed by programs dynamically.
Distance in meters traveled or the angle of longitude measured eastward (positive or negative) from either a defined north-south grid line or a meridian.
See: UTM zone for more information.
Acoustic back scatter data recorded for a particular echo or set of echoes.
Used by Simrad to describe the echo of a single target as summarized in Ex500 echotrace (E) telegrams.
See also: Bottom echo trace
Echocoastline
A utility program that converts map files from formats that are not supported in Echoview to the .mif format.
See: About Echocoastline for more information.
Echogram
An echogram is a standard method of displaying echosounder data. The Y (vertical) axis is used for depth, which increases towards the bottom of the screen. The X (horizontal) axis is used for time, which increases towards the right hand side of the screen. Individual points are color-coded to represent the strength of the returned signal at that time and depth.
See: Display page of the Variable Properties dialog box for more information.
EchoListener
A digital data logger (manufactured by SonarData) for logging data from single beam echosounders.
Echolog 60
A program that reads, broadcasts and compresses Ex60 raw data files as they are being written.
See: About Echolog 60 for more information.
Echosim 60
EK60 simulator program distributed by Myriax for testing Echoview and Echolog 60.
See: About Echosim 60 for more information.
Echozip 60
A program for compressing raw data files that were logged from a Simrad Ex60.
See: About Echozip 60 for more information.
Echolog 500
A program that logs EK500 compatible telegrams being logged by a Simrad Ex500 or Ex60 echosounder.
See: About Echolog 500 for more information.
Echosim 500
EK500 simulator program distributed by Myriax for testing Echoview and Echolog 500.
See: About Echosim 500 for more information.
Old name for Echolog 500.
See: About Echolog 500 for more information.
Echosim EK
Old name for Echosim 500.
See: About Echosim 500 for more information.
The calibration constant of the echosounder. Used in Echoview only for EchoListener data. Other echosounders use specific names for their calibration constants (e.g. Transducer gain, Receiver sensitivity, Receiver gain ...).
EK500 logger
A program used to log data from a Simrad Ex500, e.g. Echolog 500.
EK500 simulator
See: Echosim 500.
Obsolete name for the demonstration version of Myriax Echolog 500. Now called Echolog_500 demo.exe
See: About Echolog_500 for more information.
Elevation is the angle between the beam axis and the vertical.
See: About beam geometry and About transducer geometry for further information.
An attribute file that stores pixel size and geographic positioning data for a corresponding raster image file. Supported ESRI world files include:
-
.jgw (for raster images in the .jpg format)
-
.jpegw (for raster images in the .jpeg format)
-
.tfw (for raster images in the .tif format)
-
.tiffw.(for raster images in the .tiff format)
See: www.esri.com for more information.
A cylindrical equidistant projection, in which the horizontal coordinate is the longitude and the vertical coordinate is the latitude.
Lines of longitude (meridians) are spaced closer together, forming rectangles with the lines of latitude (parallels) instead of squares. There are two standard parallels, resulting in less distortion at mid latitudes, but causing distortion at the Equator.
A synonym for Equivalent two-way beam angle.
Equivalent 2-way solid beam angle
Terminology used in Echoview 2.10 and previous. Now called Equivalent two-way beam angle.
Equivalent two-way beam angle, Y (dB re 1 Steradian)
y is the solid angle at the apex of the ideal beam, which would produce the same echo integral as the real transducer when targets are randomly distributed in space. y has units of Steradians. (MacLennan and Simmonds, 1992) Y = 10log(y) and has units of dB relative to one Steradian.
Ethernet
A broadcast networking technology. All machines on one ethernet broadcast packets on the wire to all other machines, and each machine listens on the wire for packets addressed to it. Typically the TCP/IP protocol is used for communicating over Ethernets.
A 48-bit number which uniquely identifies a network adaptor. This number is hard-wired into the adaptor hardware. It is usually represented with 12 hexadecimal digits, for example "00-00-01-00-a8-2a". Sometimes called the MAC address.
Ethernet telegrams
EK500 compatible telegrams broadcast on an Ethernet by a Simrad Ex500 or Ex60 echosounder.
Echoview file: a file used to organize echosounder data files into manageable units and to store the results of on-screen editing.
See: About File sets for more information.
A collective term for the Simrad EA500, EK500 and EY500 echosounders.
Exception: When used in relation to live viewing, Ex500 refers only to EK500 and EA500.
A collective term for the Simrad EK60, EA600, EA400 and EQ60, ES60 and EY60 echosounders.
Exception: When used in relation to logging EK500 compatible telegrams, Ex60 refers only to EK60, EQ60, ES60 and EY60; the EA600/400 cannot log these types of data.
That line above which all data are ignored in an Echoview analysis. The exclude above line is selected on the Analysis page of the Variable Properties dialog box. Each variable may have its own exclude below line.
It is typically used to exclude near-field effects and transducer ring-down often visible at the top of an echogram from the analysis.
See also: Exclude below line.
Exclude below bottom
Obsolete term from version 1.
See: Exclude below line.
A superceded analysis variable from pre 3.00 versions. Superceded by Exclude_below_line_depth_mean and Exclude_below_line_range_mean.
That line below which all data are ignored in an Echoview analysis. The exclude below line is selected on the Analysis page of the Variable Properties dialog box. Each variable may have its own exclude below line.
It is typically used to exclude the bottom echo trace from the analyses.
See also: Exclude above line.
Data that falls within an analysis domain but are excluded by either an exclude below line, an exclude above line or by bad line status.
Exclude fixed surface layer
Obsolete term from version 1.
See: Exclude above line.
The Exclude below and Exclude above lines. Data outside the exclusions lines (that is below the exclude below line or above the exclude above line) are excluded from all analyses. See About lines and About analysis domains for further information.
Export
Export data to a data file (e.g. export underlying data or Sv data or analyses).
A function which is used to define the opacity of 3D objects displayed in the Scene window over the scene time window. The fade function is selected on the Time Slider Properties dialog box from the Scene window.
Focus
Can refer to either a window (see active window) or control. In either case the title bar will be highlighted and input from the keyboard will be received.
Instrument scanning data is partitioned into frames to facilitate schools detection. A frame represents a single scan of a volume of space (water). A frame is considered to be a single scan.
See: About frames
The frequency of sound transmitted for a ping.
This is a setting on the Calibration page of the Variable Properties dialog box for most acoustic variables.
It is mainly intended for record keeping purposes and is not generally used in calculations. However, the Frequency Response graph and Ex60 Power to Sv and TS algorithm do use this calibration setting.
The position of the point at the geometric center of an object - that is, the center of mass assuming the object has uniform density. This is a geometric property alone - compare with center of mass and centroid.
Information that is used to describe the position and size of objects in the real world.
A georeferenced image file based on the TIFF image format. GeoTIFF files share the same file extension as TIFF files (.tif, .tiff) but include additional header tags that store georeferencing information.
See: GeoTIFF File Interpretation dialog box for more information.
Gray Level Co-occurrence Matrix.
See: About the GLCM and textures for more information.
Data that falls within an analysis domain but are not excluded as bad data, no data or excluded data.
Global Positioning System.
A measure of position at specific moment in time that was logged by a GPS receiver. Cruise tracks to which smoothing has not been applied are created from GPS fixes.
Note: Echoview assigns a fix status to GPS fixes but does not alter the coordinates.
The quality status of the position (latitude and longitude) of a ping where the position was determined by interpolation from GPS fixes.
See: About Cruise track for more information.
A division of echogram data into layers and intervals using depth/range grid lines and time/distance grid lines respectively.
A grid is defined on the Grid page of the Variable Properties dialog box.
One of several possible ping modes used by scanning sonars. The multibeam echogram displays a 360 degree flat or conical beam fan (depending upon the tilt angle). Beam numbering is instrument specific. Refer to Echoview supported data file format details for your echsounder.
A H-mode variable may be target-locked by specifying a partner V-mode variable.
A measure of the extent of an object (specifically a region, cell, region-cell intersection or selection), in the vertical direction. This term is used in depth mode. Thickness is the analogous term in range mode.
See also: Thickness_mean and Height_mean.
The direction in which the fore-alongship axis of a platform is pointing.
Hemisphere
Northern or southern hemisphere of the earth.
Hidden object
Hidden object was terminology used prior to Echoview 4.40 for an unavailable object.
From Echoview 4.40 on, a hidden object is an object (variable, transducer, platform or line) that is not displayed in the current view on the Variables and Geometry window.
Technique of using an echosounder, where the transducer points horizontally. Used especially in shallow waters such as rivers, lakes and reservoirs where a transducer pointing vertically (downwards) cannot sample effectively. In some cases the data from horizontal and vertical beaming can be combined to sample shallow and deep waters simultaneously.
See: Horizontal beaming references for more information.
Hypertext Markup Language is a language for the creation of hypertext pages on the World Wide Web.
See: http://www.w3.org/MarkUp/ for more information.
An option on the File menu that is used to import region definition files (*.EVR), line definition files (*.EVL), HTI tracked echo files (*.ECH) or virtual variables into the current EV file.
See: Importing in Echoview for more information.
In Echoview, the display underneath an echogram that optionally reports ping status, mean Sv or maximum Sv on a per-ping basis. This definition is different from that found in Simmonds and Maclennan. The Simmonds and Maclennan definition for integram is similar to the Echoview integration line.
See: Understanding echograms for more information.
In Echoview this is a property sometimes held by a 3D point.
For 3D points in a 3D polyline this will be the value of Intensity read from the .epl file when the polyline was imported.
For 3D points in a 3D region track this will be the mean Sv of the 3D region the point represents. If the mean Sv could not be calculated at the time of detection this value will be -9.9e37. See Integration from scenes for further information.
Calculation of the echo integral and other analysis variables.
Divisions on the time/distance axis of a grid, i.e. intervals are delineated by vertical bands on an echogram.
See: About interval and layer values in export files for more information.
Internet protocol. The network protocol on which the Internet and many private networks are based on which the TCP and UDP protocols operate.
An address which uniquely identifies a computer using the Internet protocol. This address is usually specified as four decimal numbers separated by decimal points, e.g.: "192.168.1.102".
IP Port
A number between 0 to 65535 used to establish individual connections on an IP networked machine. Datagrams on a network are addressed to a port at an IP, the complete address often written as: "192.168.1.102:80" for port 80 on the machine at 192.168.1.102:80.
Local area network. Typically a TCP/IP Ethernet.
LAN adaptor number. Used internally by Microsoft operating systems to distinguish between multiple adaptors on the same computer.
Latitude measures the north-south position of locations on the Earth's surface relative to a point found at the center of the Earth. Echoview supports the input of latitude and longitude in both decimal degree and degree and minute formats. Echoview accepts values between -89.9999 and +89.9999 decimal degrees for latitudes in the southern and northern hemisphere respectively.
See: About degrees and minutes for more information.
Divisions on the depth/range axis of a grid, i.e. layers are delineated by horizontal bands on an echogram.
See: About interval and layer values in export files for more information.
Layer Depth Lower - A superceded analysis variable from pre 3.00 versions. Superceded by Layer_depth_min and Layer_range_min.
Layer Depth Upper - A superceded analysis variable from pre 3.00 versions. Superceded by Layer_depth_max and Layer_range_max
A temporary line drawn on an echogram when creating or editing lines. It can be cleared at any time without affecting the lines in Echoview, or used to define a new editable line or modify an existing line (the active line). See the Line draw tool and About lines for further information.
Left-right
On HTI echosounders, the equivalent of Echoview's major-axis.
A calibration setting for variables derived from Simrad Q and E telegram data when data has been logged with an embedded transducer draft.
See: Logged draft warning for more information.
Longitude measures the west-east position of locations on the Earth's surface relative to a circular arc called the Prime Meridian that is in-line with the location of the astronomical observatory at Greenwich, England. Echoview supports the input of latitude and longitude in both decimal degree and degree and minute formats. Echoview accepts values between -180.0000 and +180.0000 degrees for longitudes in the western (i.e. west of Greenwich) and eastern hemisphere respectively.
See: About degrees and minutes for more information.
Longitudinal axis
See: Alongship.
Data compression where all information from the original file is preserved.
Lower display depth
The deepest depth that can be displayed on an echogram. Set on the Display page of the Variable Properties dialog box.
One of the two axes across the face of a transducer. The major-axis is typically the horizontal axis or the athwartship axis depending upon context (fixed platform or mobile platform).
See: About beam geometry for details on specific manufacturer's preferred terminologies.
The format in which Echoview accepts maps for display on cruise tracks. See Map files.
Marker region
A region whose purpose is to draw the operators attention to a section of the echogram. The region's name and annotation properties can be used to enter additional information.
See: About regions for more information.
A linear algebra manipulator and viewer package.
A superceded analysis variable from pre 3.00 versions. Superceded by Last_layer_depth_stop and Last_layer_range_stop.
Threshold applied to echogram data.
A superceded analysis variable from pre 3.00 versions. Superceded by Exclude_above_line_depth_mean and Exclude_above_line_range_mean
The median value in a list of values, is determined by sorting that list of values and choosing the value in the middle of the resulting list. This operation is valid only for lists with an odd number of entries. For example the median of a list of 9 values would be the 5th value in the sorted list.
A superceded analysis variable from pre 3.00 versions. Superceded by First layer_depth_start and First_layer_range_start.
One of the two axes across the face of a transducer. The minor-axis is typically the vertical axis or the alongship axis depending upon context (fixed platform or mobile platform).
See: About beam geometry for details on specific manufacturer's preferred terminologies.
Minimum Sv is the weakest Sv value displayed with a color (i.e. not white) on the echogram.
A dialog box that requires a response e.g. click OK or Cancel. An application cannot continue until a response has been entered.
A term used in Echoview to refer to:
-
Any data of ping mode 2, 3, 4 or 5
-
Any multibeam sonar, scanning sonar or data from such a device
A communications device that multiplexes (combines) several signals for transmission over a single medium. May be abbreviated to mux.
Common abbreviation for multiplexor.
The beam in a multibeam acoustic variable that is pointing vertically down or is closest to pointing vertically down.
Nautical area scattering coefficient.
This was referred to as sA in Echoview 1.x.
See: ABC and NASC for more information.
One point in a grid of similar points that Echoview creates for exporting region inspection data. This grid is configured on the Export region inspection data dialog box.
Noise power
Background noise power is the power (dB re 1 Watt) present at the transducer due to background noise. Echoview now uses the Noise Sv at 1 m to specify the background noise level.
A deprecated term in Echoview, which refers to beam width.
The measured pulse length divided by the transmitted pulse length yielding a non-dimensional (normalized) value which is 1 when the measured pulse length is equal to the transmitted pulse length.
Distance in meters traveled or the angle of longitude measured northward (positive or negative) from either a defined east-west grid line or a meridian.
See: UTM zone for more information.
NTFS
New Technology File System. The standard file system for Windows NT, 2000 and XP, replacing the FAT file system used in earlier versions.
The Wavefront .obj file format is a standard 3D object file format. Obj files are text based files supporting both polygonal and free-form geometry (curves and surfaces). The color and materials of 3D object surfaces are stored in a related .mtl file.
See: Supported features of .obj and .mtl files for more information.
Observed mean energy
Synonym for Sv or Volume backscattering strength.
A variable upon which an operator will act to produce a virtual variable.
A list of folders where the operating system looks for executable files if it is unable to find the file in the working directory. It is specified using the environment variable PATH. See Microsoft Windows help for information on how to modify this variable.
Phase data
A synonym for angle data.
A transmission of an acoustic pulse (a short burst of sound at the operating frequency of the sonar) from a transducer and the echo trace measured from that pulse (and the representation of that echo trace in Echoview).
In Echoview, acoustic variables are made up of a series of pings.
See also: About pings, pulse
In Echoview, the ping geometry is:
-
the time stamp of a ping
-
the start range and stop range of a ping
- the number of samples in a ping
and, for multibeam pings also:
-
the number of beams in the ping
- the number of samples in each beam in the ping
See: Using multiple operands for more information.
A property of each multibeam ping in Echoview, which defaults to 0. It has a value of 1 and 2 respectively for any two pings in a target-locked ping pair which do not have the exact same time. Otherwise it will be 0. It can be seen in multibeam data exports.
The pings in each variable in an EV file are sequentially numbered by Echoview, starting at 0. This is independent of any numbering those pings may or may not have in the data files from which they are read.
A status number associated with each ping. It can take one of 10 values which can be defined by the user on the Ping status page of the EV File Properties dialog box. It is selected for display on the Display page of the Variable Properties dialog box.
See: About ping status and Understanding echograms for more information.
Rotation of the platform (typically a vessel) about the Y axis (the athwartship axis).
See: About pitch data for more information.
The basic unit of composition (picture cell) of a 2D image on a computer screen or similar display. This is analogous to the voxel for a 3D image. The intensity of a pixel is dependent on the display medium. For example: color intensity may be represented in three dimensions such as such Red, Green and Blue or gray scale intensity may be represented in gray level numbers.
A logical object in Echoview representing a fixed or moving structure from which data were logged. A moving platform has a position and heading which vary with time. Platform properties can be seen on the Position page of the Platform Properties dialog box.
The platform defines a X, Y, Z coordinate system for the relative placement of transducers, GPS antenna and the water level. See About transducer geometry for further information.
The platform is represented by an shape on the Variables and Geometry window.
The platform is represented by the apex of a triangular outline on a 3D cruise track on the Scene window. See About Scene animation for more information.
The geographic location of a platform. The platform position is plotted as the location of the system reference point which is implicitly defined on the Position page of the Platform Properties dialog box.
See: About transducer geometry for further information.
Pulse Length Determination Level. This defines how many decibels below the peak value of a detected pulse Echoview should consider when determining the pulse length during single target detection.
See: Single target pulse properties for more information.
Variables that contain a time-series of measurements associated with geographic location of a platform.
See: About variables for more information.
A program that was provided with Echoview 3.10 and earlier to convert Digital Chart of the World (DCW) map files into the .mif format. Pts2mif was superceded by Echocoastline.
The duration (typically in milliseconds) of a pulse (ping).
See also: Transmitted pulse length and Received pulse length.
On Simrad Ex500 series echosounders a setting of this name can take the value of Long, Medium or Short which must be specified on the Calibration page of Variable properties dialog box for the Power to Sv or TS calculation. Note: This setting is not required for data from a Simrad Ex60 series echosounder. See also Band width.