# 1D

**1D** or **1-D** is a common abbreviation for **one-dimensional,** indicating a mathematical or geometric dimension .

It means that each point of a **1D object** only needs a number (coordinate) for its position .

As a rule, 1D objects have a linear structure (for example a number line or a gray scale), or they can represent a different scalar quantity through a length . Scales are also one-dimensional (for example, straight for liquid thermometers or circular for many pointer measuring devices ).

In contrast to this, a 2D object represents, for example, an area in which each point requires two numbers for its position, for example (x, y) on a map . A 3D object usually represents a body , the points of which are only determined by three coordinates (e.g. x, y, z).

In many cases, time is viewed as a separate, prominent dimension . However, this can be misleading, because the time axis is almost always linked to two or three spatial dimensions and therefore, for example, turns 3D objects into 4D objects.

“Stretched lines” that largely or entirely coincide with their axis are to be regarded as one-dimensional . A geodetic line on a surface also has a 1-D character. But not all linear structures have to be one-dimensional. examples are

- a belt structure on which, in addition to the " running dimension " (length), the specification of a width is necessary,
- a surface curve whose lateral deviation is indicated by specifying a curvature or the like. needs to be defined.