Vertical position or vertical location is a position along a vertical direction (the plumb line direction) above or below a given vertical datum (a reference level surface, such as 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.
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:
^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.
^Nash, Mike, Exploring Prince George: A Guide to North Central B. C. Outdoors, Vancouver: Rocky Mountain Books, 2004, p. 105.
Further reading
IOGP (2018) Geomatics Guidance Note 24: Vertical data in oil and gas applications, International Association of Oil & Gas Producers (IOGP), Geomatics Committee, Geodesy Subcommittee. Report 373–24, April 2018. [1]