Having consistent terminology improves understanding of difficult concepts. These terms are used throughout Fling Units, both in the guides and the code itself.

Dimensions

Everything we want to measure falls under what we will call a dimension. A dimension represents the sort of thing we are interested in measuring, for example, distance or time. Dimensions are not cross-compatible - we cannot combine measurements of different dimensions directly. We can, however, define more complex dimensions by either multiplying or dividing simpler dimensions. For example, velocity could be defined as distance divided by time. We refer to these as derived dimensions.

Units

In order to measure something along a dimension, we need to agree on a reference amount of the thing we are measuring. We can express our measurement in terms of this reference amount so that others can understand our measurement. For example, if we are measuting distance, we might use a unit such as a meter as our reference, and provide our measurement as a multiple of meters. Hopefully, those reading our measurement will understand what we mean by a meter and thus understand our measurement.

Just as dimensions can be derived, so can units. A derived unit is typically represented by its component parts. For example, velocity could be represented in meters per second, where the distance component of the velocity is represented by meters and the time component is represented by seconds. This is not a requirement, however, and some units exist to simplify the use of what would otherwise be a more complicated derived unit. For example, the volume dimension is a common dimension and has its own units, such as the liter, even though it could be represented as cubic distance.

Prefixes

Because things we want tomeasure vary dramatically in magnitude, even within the same dimension, we might insert a prefix before our units. For example, if I am measuring the distance between two cities, I might use kilo meters, but if I am measuring the length of my pinky, I might use centi meters. Each prefix represents a multiplier for the unit in question.

These prefixes tend to be associated with metric units, and so are known as "metric prefixes." This is because other systems have solved the magnitude problem by introducing other units, for example miles, feet, and inches. Fling Units does not prevent you from using these prefixes with non-metric units, however, so you are free to create milli miles if that suits your needs.

Measurements

By putting all of these concepts together, we can finally create a measurement. A measurement is simply a multiple of some unit, typically written as the multiplier followed by the abbreviation for the unit. For example, "50 m" would indicate 50 times the length of one meter.

Changing the unit associated with a measurement is straightforward, given that both units share the same dimension. Fling Units performs this calculation for us, and is one of the main reasons for its existence. Our systems may receive inputs using any number of units because some people may be more comfortable with particular units, or because their measuring equipment provides only those units.