Ordinarily produces: feet ft (metres m).
If one of feet and metres is omitted, it will be calculated by conversion of the other (which must be numerical or an error will be displayed).
Setting switch to any non-empty value causes the metric value to be displayed first.
Set round to define the degree of rounding (e.g. 0 for no decimal places).
Setting link to any non-empty value causes the units to be wikilinked to foot (unit of length and metre.