Measuring Units in Fantasy

From 1ste Gimnechiske Wiki

In addition to Historical units and ISO Standard units, fantasy allows you to make up your own unit system. But before throwing units around, you need to think of the definitions and the usage of the units. It is better to make a culture based upon the stantard or historical units I have defined, than to make a sloppy and caotic unit base.

Usage

Most units will have a clearly defined usage, some of which can be straight forward such as in the metric system, where all we look at is what is measured (volume, length, area, time), or it can be connected to the exact measuring (such as many historic units for trade goods). How a comodity is measured reflects on how it is traded, and how values are set. For instance it can be impossible to buy ropes in other lengths than whole fathoms, as fathoms is the measurement of rope (that way it is impossible to buy 50 feet of rope, though 9 fathoms is just more than 50 feet, you can try that instead).

Definition

The definitions of measuring units must make a sence. Pits of body parts, and other such definitions is easy to use in every day, but when translating between systems, or when there is a dispute, there must be a standard to set it up against.

Wizards and Alchemists might not appriciate much these forms of natural definitions, and would probably push to get a standardized system through. The names of the alchemical units might be the same as the units used by merchants, though the definitions might be different. For instance, an ounce have at least three different definitions, all of which might be true in the same area at the same time, though one is used by the baker, one by the apotechor and one by the bar man. Three different areas of use, three different definitions, all true.

In modern or future type settings, uniformed standards should often be used, either an Imperial system, or an ISO type system, where a unit is the same no matter what it measures (an ounce is an ounce) and recalculation to other uniform systems can be done by multiplying or dividing on fixed factors.

Relation

There must be a logic between the relations, atleast between units used for the same type of measuring. For instance, the difference between two units to measure the weight of grain will need to be logical according to the cultures numbering system, or related to the usage of grain. For instance, a culture using a hexadecimal (16) number system will not devide a master unit in tenths.