How to support styling of the complete set and individual symbols

[chris-little]

This as originally part of Issue #25, which is now closed.
The WMO specification allows some symbols to be displayed in another colour (red instead of the default black) to convey slightly different semantics, to avoid confusion with other symbols and to ease interpretation of complex combinations.

SVG supports a number of appoaches, such as an external style sheet, inline style sheets, inline styling, and contextual styling from, for example, CSS or XSLT.

It is not clear which approach is best.

A typical use case is to plot many hundreds of symbols, some black, some red, as quickly as possible.

Do any SVG users/developers have any real world experience in various technology stacks please?