A geodeticdatum is sometimes also called a benchmark.
2000, Nuno Sergio Marques Antunes, “The Importance of the Tidal Datum in the Definition of Maritime Limits and Boundaries”, inMaritime Briefing, volume 2, number 7, International Boundaries Research Unit, University of Durham, page 5:
In a strict sense, atidaldatum can be understood as the reference plane (or surface) to which the height of a predicted tide is referred.[…]Sounding and chartdatums are low waterdatums, that is, they refer to the level of the water surface at low tide. Nonetheless, there are alsodatums based on high water levels.[…]These two differentdatums may be included in the broader category ofverticaldatums, which comprises any plane or surface used as a reference to measure vertical distances (such as depths, drying features, heights on shore, etc.).
2007, Roger F Tomlinson,Thinking about GIS: geographic information system planning for managers:
Datums are another important map aspect related to projection. Adatum provides a base reference for measuring locations on Earth's surface.
2012, Yong-Qi Chen, Yuk-Cheung Lee, chapter 2.3, inGeographical Data Acquisition:
For horizontal measurements [on the Earth], we fix a mathematical body of Earth in space using a Cartesian coordinate system. After that, a separate coordinate system is created over the surface of this body to generate horizontal coordinates. A mathematical earth body fixed in space makes up thehorizontaldatum.
datum (third-person singular simple presentdatums,present participledatuming,simple past and past participledatumed)
To provide missing data points by using a mathematical model toextrapolate values that are outside the range of a measuring device.
1982, Paul M. Tucker,Pitfalls Revisited - Issue 3,→ISBN, page 6:
Removing the effects of any period of deformation bydatuming or flattening selective reflection horizons should restore the structure prior to thedatumed horizon, or the amount of deformation above thedatumed horizon.
1998, Stuart Fagin,Model-based Depth Imaging,→ISBN, page164:
On the left the stacking velocity functions aredatumed to sea level and show great disparity.
2014, Hua-Wei Zhou -,Practical Seismic Data Analysis,→ISBN, page62:
On the other hand, if we have a sufficiently accurate near-surface velocity model, we may apply wavefielddatuming to convert the raw data into new data as if they were recorded along a datum below the near surface (Box 2.3).
Philip Babcock Goveet al., editors (1961), “materialn”, inWebster's Third New International Dictionary[…], volume I (A to G), published1981,→ISBN, page577
FromMiddle Dutchdatum, fromLatindatum(“given”,past participle) (from the practice of signing letters in Latin by noting the date on which they were dispatched). CompareEnglishdate.
"datum", in Charles du Fresne du Cange’sGlossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
, Oxford:Oxford University Press, launched 2000.
