Section 23 Units of Measure
Units of measure can be given xml treatment too with the
quantity element. In LaTeX, the
siunitx package is loaded to achive unit handling. Since that package only offers SI units, some other common units will be added by PreTeXt in the preamble. In HTML, the capabilities of
siunitx are simulated, weakly. Note that at present, you should not attempt to use the
quantity element within a math environment.
The value of gravitational constant \(g\) is 9.8 m⁄s2. Force is measured in kg·m⁄s2, also known as one N. A quantity with rather ridiculous units is 23 µha23⁄°C·s2. One Hz is the same as 1⁄s. You can have a unitless quantity, like 42, which may help with consistency between such numbers and units in the LaTeX output. Some non-SI units are available, such as the absurd °F·ft·lb⁄gal. The LaTeX command
\pi is recognized within
mag in conversions to HTML, which is consistent with the behavior with a conversion to LaTeX, for example there are 2\(\pi\) rad in a full circle. This is a similar quantity with multiple occurences of
\pi to test a particular template used for HTML output. It is not meant to make any sense: 21\(\pi\)45\(\pi\)234\(\pi\)890 rad.
For a full list of the allowed units and prefixes, see
pretext-units.xsl. If you have a need for more units, they need to be added to
pretext-units.xsl in the section that deals with units which are not part of
siunitx by default. Note that the
mag element should come first, followed by the
unit element, followed by the