Vertical position

Source: Wikipedia, the free encyclopedia.

Vertical position or vertical location is a

mean sea level
). Vertical distance or vertical separation is the distance between two vertical positions. Many vertical coordinates exist for expressing vertical position: depth, height, altitude, elevation, etc. Points lying on an
equigeopotential surface are said to be on the same vertical level, as in a water level
.

Definitions

The International Organization for Standardization (ISO), more specifically ISO 19111, offers the following two definitions:[1]

  • depth: "distance of a point from a chosen reference surface measured downward along a line perpendicular to that surface."[1]
  • height: "distance of a point from a chosen reference surface measured upward along a line perpendicular to that surface";[1]

ISO 6709 (2008 version) makes the following additional definition:

  • altitude: "height where the chosen reference surface is mean sea level"[1]

The International Civil Aviation Organization (ICAO) offers similar definitions:[2]

  • altitude: "the vertical distance of a level, a point or an object considered as a point, measured from the mean sea level (MSL);"[2]
  • height: "the vertical distance of a level, a point or an object considered as a point, measured from a specific datum."[2]

ICAO further defines:

  • elevation: "the vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level."[2]

I.e., elevation would be the altitude of the ground or a building.

Derived quantities

Several physical quantities may be defined based on the definitions above:

Units

Vertical distance quantities, such as

feet
, etc.

Certain vertical coordinates are not based on

geopotential numbers
have units of m2/s2. Normalization by a constant nominal gravity value (units of m/s2) yields units of metre, as in
physical space, as would be measured with a ruler or tape measure
. Sometimes a geopotential metre (symbol gpm or m') or dynamic metre is introduced for emphasis.[3][4] However, this practice is not acceptable with the International System of Units (SI).[a]

Another non-SI unit is the vertical metre, introduced when there may be confusion between vertical, horizontal, or

slant distances
. It is used for distance climbed during sports such as mountaineering, skiing, hiking, running or cycling[6] In German-speaking countries the abbreviation 'Hm' for Höhenmeter ("height metre") is used; if it is preceded by a '±' it refers to the cumulative elevation gain.

Measurement

Various instruments and techniques may be used for measuring vertical position:

Phenomena

Many physical phenomena are related to vertical position, as driven by gravity:

See also

Notes

  1. ^ The Guide for the Use of the International System of Units, section 7.5 (Unacceptability of mixing information with units), states:[5]

    When one gives the value of a quantity, any information concerning the quantity or its conditions of measurement must be presented in such a way as not to be associated with the unit.

References

  1. ^ a b c d "ISO 6709:2008(en) preview". www.iso.org. ISO. Retrieved 8 June 2016.
  2. ^
    Chicago Convention on International Civil Aviation (ICAO Doc. 7300
    ).
  3. ^ World Meteorological Organization - Guide to Meteorological Instruments and Methods of Observation - Preliminary seventh edition - WMO-No. 8 - Secretariat of the World Meteorological Organization – Geneva – Switzerland - 2006
  4. . Carnegie Institution of Washington publication. Carnegie Institution of Washington. p. 13. Retrieved 2023-10-05.
  5. ^ Thompson, Ambler; Taylor, Barry N. (2018-11-10). "Guide for the Use of the International System of Units (SI)". NIST. Retrieved 2020-12-09.
  6. ^ Nash, Mike, Exploring Prince George: A Guide to North Central B. C. Outdoors, Vancouver: Rocky Mountain Books, 2004, p. 105.

Further reading

External links