Language selection


Hydrographic Survey Management Guidelines

10 Abbreviations, Acronyms, Definitions, and Terms

The extent to which a measured or enumerated value agrees with the true value.
Bathymetric surface
A surface model of the seafloor as determined by creating an interpolated (or not) grid of depths from the observed depth samples (Also called seabed surface model, seafloor surface model, seafloor model).
Bench marks
Stamped, fixed elevation tablets from which sounding and/or chart datum may be recovered, and against which the zero setting of tide gauges and tide staffs are checked.
Bottom search
A method of exploring the seabed, which attempts to provide complete coverage of an area for the purpose of detecting all features, addressed in this publication.
Canadian Coast Guard
A DGPS service provided by Canadian Coast Guard.
Circular Error Probability
The Canadian Geodetic Vertical Datum 1928 (CGVD28): Official height reference system in Canada The reference frame for the CGVD28 is the mean sea level at six tide gauges in dates of 1928.
CHS Standard Station Markers (Two main types exist):
CHS Tablet commonly known as a rock post, it is a circular metal disk, 7.6-cm (3 inches) in diameter, with Hydrographic Service Canada inscribed around its periphery. This type of tablet is usually cemented into bedrock or a concrete block.

CHS Rectangular Aluminium and Steel Rod with Spread-Foot commonly known as a terminus or soil post. One side of the upper portion is usually stamped Hydrographic Service Canada. This type of marker is usually driven into the soil.
Confidence levels
The probability that an error will not exceed the specified maximum value.
Conspicuous features
Any conspicuous natural feature that may be used by a navigator for positioning purposes (mountain peaks, hills, islet, etc.). These features are usually positioned by intersection or resection.
Conspicuous objects
Any conspicuous man-made object that may be used by a navigator for positioning purposes (aeronautical beacon, church spire, chimney, cross, silo, water tank, television tower, etc.). A check position is necessary and the positions must agree within one meter.
Control Network
A network of permanently marked control points having their geographic positions established to firm third order accuracy or better.
A quantity, which applied to an observation or function thereof, will diminish or eliminate the effects of errors and give an improved value of the observation or function. The correction corresponding to a given error is of the same magnitude but of opposite sign. (IHO S32 ed.1994, #1079)
Conductivity / Temperature / Depth / Salinity
Combined Uncertainty and Bathymetric Estimator
Differential Global Positioning System
Digital Terrain Model
Electrical centres
The exact location of the electrical centre at antennae sites of any GPS reference or integrity monitor stations.
Is the difference between an observed or computed value of a quantity and the ideal or true value of that quantity. (IHO S32 ed.1994, #1671)
FAT form
Fixed Aids Tabulation from
Fixed aids
Any stationary man-made structure erected for navigational purposes (day beacon, lighthouse, ranges, range lights, etc.). These are surveyed to third order accuracy, and then described and recorded on the Fixed Aid Tabulation Form.
The field of statistics, which deals with estimating the confidence of interpolated values, derived from measurements of geo-referenced data.
Global Positionning System (satellites)
Geodetic Survey Division of Natural Resources Canada
Hydrographic Data Center
Higher High Water Large Tide
Hydrographer in Charge
InterFeroMetric Sonar
ISO 9001
A family of standards for quality management systems.
International Organization for Standardization
Lower Low Water Large Tide
Line of Position is a line indicating a series of possible positions of a craft, determined by observation or measurement. It is also called position line. (IHO S32 ed.1994, #2848)
MultiBeam Echo Sounder
Is the information describing characteristics of data, e.g. the accuracy of survey data.

ISO definition: Data (describing) about a data set and usage aspect of it. Metadata is data implicitly attached to a collection of data. Examples of metadata include overall quality, data set title, source, positional accuracy and copyright.
MS (Semi-Permanently Marked CHSStations)
CHS control points marked by a drill hole, iron rod, pipe, or ring of nails, etc., considered to be of semi-permanent nature, usually described, and recorded on the form "Description of Survey Station or Object."
Multi-Transducer Echo Sounder
Position Dilution of Precision
PMS (Permanently Marked CHSStations)
CHS control points that have been permanently marked by a rock-post or soil-post, described and recorded on the form "Description of Survey Station or Object."
A statistical measure of repeatability of a value, usually expressed as variance or standard deviation of repeated measurements.
Product Specification and Coding Guide
Quality Management System
Quality assurance
All those planned and systematic actions necessary to provide adequate confidence that a product or a service will satisfy given requirements for quality.
Quality control
All procedures which ensure that the product meets certain standards and specifications (IHO S32 ed.1994, #4115)
Reference marks
Supplementary marks established to enable relocation of main control points, antennae locations for major positioning systems, fixed aids, etc. Normally three referenced marks are used to witness the position in question and are identified by inscribing Ref 1, Ref 2, etc., on standard station markers.
Real-Time Quality Assurance
Real Time Kinematic GPS.
Single Beam Echo Sounder
secondary control
A network of control points or individual points of a localized nature utilized for shoreline plots, electronic tacheometer (total station) work, etc., whose geographic positions may be established to a slightly lower order of accuracy than main control points.
Aids Program Information System
Sound Speed Profile
Speed Through the Water
Sound Velocity Profile
Total Propagated Uncertainty
Unmarked CHSstations
Normally refers to secondary control points not marked and primary control stations that were not marked due to land usage e.g. area under construction, agricultural purposes, etc.
Wide Area Differential Global Positioning System
A World Geodetic System that is currently the reference ellipsoid being used by the Global Positioning System
Expendable Bathythermograph
Expendable Sound Velocimeter
Date modified: