add functionality to convert symbols to fonts and unicode support

[wxtim]

Is it worth adding scripts to convert these svgs to

1. Fonts
2. Local unicode symbols in the local symbols section of the unicode space.

[chris-little]

Both are good ideas, but think (2) Unicode Private Symbol Space of 2000 is front runner and will get most mileage (sorry about all the metaphors).

The problem with (1) is choosing which font formats. Even SVG Versions 1, 1.2 and 2 haven't quite got it right yet, though I am open to being corrected.

[dopplershift]

MetPy went to the trouble of producing a TTF font from these images, at least for weather symbols. We elected to use the private symbol space, starting at 0xE900.

[chris-little]

Thanks for this info. I think using the Basic Plane Private Use Area (U+E000–U+F8FF) of 6400 symbols is a good decision, as I am not aware of the use of the 'higher' planes enabled by ISO10646: Private Use Area-A (U+F0000–U+FFFFD) and Private Use Area-B (U+100000–U+10FFFD), with 64K symbols each, and possibly used in China.
Is there any reason for starting at 0xE900 rather than nearer 0xE000, like 0xE001?

[dopplershift]

I’m honestly not sure why we went with 0xE900, other than maybe to be less likely to conflict.

[ronaldtse]

Hello folks! @chris-little asked during the most recent OGC DocTeam session on whether Metanorma supports these symbols from the unicode private plane. Is there going to be an official font for these?

(we're tracking it here: metanorma/metanorma-ogc#24)