Editing Module:Val/units/doc (section)

==== Scale ====

For scaling a unit to sort properly, you need to pick a number for a sorting factor. 
There are numerous examples at [[Template:Val/list]] and at [[Template:Val/sortkey/unit]]. A [[system of units]] will have its base units, for example 1 bit; then the scale for sorting a kilobyte unit is then 8000 (eight bits per byte, times a kilo, or thousand). Or a year scale is seconds so that all ''times'' sort by seconds, which is a base unit.  In general the scale shows to be "base unit" of the same type times the "SI prefix", and if it's not that simple, then the unit system's number has associated a number to it, such as Avogadro's number.  

For example, the following defines a unit with code <kbd>billion</kbd>, symbol <kbd>billion</kbd>, link [[1,000,000,000]], and scale <kbd>1e9</kbd> ({{val|1|e=9}}).  After the following entry is saved to the database
<pre>
billion            billion          1,000,000,000          1e9
</pre>
<nowiki>{{val|2|u=billion}}</nowiki> would start sorting after <nowiki>{{val|98.7|e=3}}</nowiki>.