> I'm looking for an ISO entity reference for a symbol used to express
> longitudinal feet. The sentence I am working on is:
> She died at sea and was buried lat. 15°50' S., long110°35'E.
What you've got there are not feet, but minutes -- sixtieths of a degree. The
correct public entity for this is ′ (prime or minute) from ISOtech (ISO
8879-1986//ENTITIES General Technical//EN). For good measure, this set also
includes ″ (double prime, or second, where a second is a sixtieth of a
minute of arc).
But, on the subject of feet (and inches), I'm not aware of a public entity for
the single-quote-like (double-quote-like) indicators. In the British National
Corpus, on the random ocasions where we managed actually to differentiate these
symbols from single and double quotes, we rolled our own: &ft; and ∈ as I