Terms for rotations

[Whistler, Ken]

Garth Wallace asked:

> I'm currently working towards a proposal to encode a set of symbols
> used in fairy chess and chess variants, and I have a question about
> naming conventions. Several of the symbols are rotations of already
> encoded symbols. ...
> 
> It's even more unclear when it comes to intermediate rotations in 45°
> increments (I'm not sure if I will include these in any proposal; I'm
> still doing research, gathering evidence of use and determining my
> scope). Arrows seem to use ordinal compass directions (e.g. NORTH EAST
> ARROW), but again these are not arrows. The names FAQ is silent on
> this.
> 
> I'm leaning towards "turned", "left rotated", and "right rotated" for
> the cardinal orientations, and have no idea what (if anything) to do
> about intermediate ones. Are there any more or less official
> preferences?

When you start talking about sets of symbols rotated into 8
orientations each, doubled again by chirality, then you really
are into the realm of a notational system -- perhaps not best
handled for encoding by simply separately encoding each symbolic
unit in each possible visual orientation.

I suggest first taking a look at what was done for analyzing a similar
problem of rotation of symbols for the SignWriting notation
system. See:

http://www.unicode.org/L2/L2012/12321-n4342-signwriting.pdf

That should give you some ideas about possible alternative approaches
for the material you are dealing with.

--Ken