Considering that depth denotes the distance below sea-level to a point on an object located below sea level, and considering that height denotes the distance to some point above the surface of the earth as measured from a point on surface of the earth, it seems there ought to be a term that denotes the distance to some point below the surface of the earth as measured from a point on the surface of the earth.

For example, suppose someone dug a mine shaft down into the earth from an elevated point, but not so far down that it descends below sea-level; what term ought we use to denote the points below the surface of the earth?

closed as primarily opinion-based by user681, Vince, PolyGeo, Jason Scheirer, Brad Nesom Jul 28 '14 at 3:33

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • This may be more suitable for posting at Earth Science. – PolyGeo Jul 27 '14 at 21:50
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    Better still... english.stackexchange.com since it contains information on language and usage – user681 Jul 27 '14 at 21:51
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    @DanPatterson: I think if it's about GIS language/usage, it's better off here -- same reasoning as for GIS programming and GIS data sets being here. – Martin F Jul 28 '14 at 3:41

You are limiting the applicability of 'depth'. You say

depth denotes the distance below sea-level to a point on an object located below sea level

This isn't strictly correct. Depth is usually used for all negative distances from any surface, not just below sea level.

In all industries and applications that I have worked with, depth is used to indicate the distance below the reference surface.

Depth is the nomenclature used in:

So 'Depth' is the word that you should use, and most people, in all kinds of industries and fields will understand you.


The term height can be used for both above and below ground measurements. My definition of height includes the vertical distance from the origin of measurement--this can be either + or -. For example, if I am standing at the bottom of a mineshaft and use my laser range finder to determine the height to the surface, the measurement may be 1000 m. Alternatively, if I am standing at the top of the mine shaft and measure the vertical distance to the bottom, the height would be -1000 m.


Since GIS is a very multidisciplinary subject, there are always going to be many differences in terminology for the same basic concept. Which is "correct" depends on the specific context.

Some synonyms for height: elevation, rise, altitude, ascent, relief, hypsography, orography.

Some synonyms for "opposite of height": depth, fall, invert, descent, bathymetry.

You can always use the same term and simply apply positive values for up and negative values for down.

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