Re: Variations and Unifications ?

From: Asmus Freytag (t) <asmus-inc_at_ix.netcom.com>
Date: Wed, 16 Mar 2016 10:34:54 -0700
On 3/15/2016 8:14 PM, David Faulks wrote:
As part of my investigations into astrological symbols, I'm beginning to wonder if glyph variations are justifications for separate encoding of symbols I would have previously considered the same or unifiable with symbols already in Unicode.

For example, the semisquare aspect is usually shown with a glyph that is identical to ∠ (U+2220 ANGLE). However, sometimes it looks like <, or like ∟ (U+221F RIGHT ANGLE). Would this be better encoded as a separate codepoint?

The parallel aspect, similarily, sometimes looks like ∥ (U+2225 PARALLEL TO), but is often shown as // or ⫽ (U+2AFD DOUBLE SOLIDUS OPERATOR). This is not a typographical kludge since astrological fonts often show it this way.
There is also contra-parallel, which sometime is shown like ∦ (U+2226 NOT PARALLEL TO), but has varaint glyphs with slated lines (and the crossbar is often horizontal).

The ‘part of fortune’ is sometimes a circled ×, or sometimes a circled +.

Would it be better to have dedicated characters than to assume unifications in these cases?
My take is that for symbols there's always that tension between encoding the "concept" or encoding the shape. In my view, it is often impossible to answer the question whether the different angles (for example) are merely different "shapes" of one and the same "symbol", or whether it isn't the case that there are different "conventions" (using different symbols for the same concept).

Disunification is useful, whenever different concepts require distinct symbol shapes (even if there are some general similarities). If other concepts make use of the same shapes interchangeably, it is then up to the author to fix the convention by selecting one or the other shape. Conceptually, that is similar to the decimal point: it can be either a period, or a comma, depending on locale (read: depending on the convention the author follows).

Sometimes, concepts use multiple symbol shapes, but all of these shapes map to the same concept (and other uses are not known). In that case, unifying the shapes might be acceptable. The selection of shape is then a matter of the font (and may not always be under the control of the author). Conceptually, that is similar to the integral sign, which can be slanted or upright. The choice is one of style. While authors or readers may prefer one look over the other, the identity of the symbol is not in question, and there's no impact on transmission of the contents of the text.

Whenever we have the former case, that is, multiple conventional presentations that are symbols in their own right in other contexts, then encoding an additional "generic" shape should be avoided. Unicode explicitly did not encode a generic "decimal point". If the convention that is used matters, the author is better off being able to select a specific shape. The results will be more predictable. The downside is that a search will have to cover all the conventions. Conceptually, that is no different from having to search for both "color" and "colour".

The final case is where a convention for depicting a concept uses a symbol that itself has some variability (for example when representing some other concepts), such that some of its forms make it less than ideal for the conventional use intended for the concept in question. Unicode has historically not always been able to provide a solution. In some of these cases, plain text (that is, without a fixed font association) may simply not give the desired answer. If specialized fonts for the convention (e.g. astrological fonts) do not usually exist or can't be expected, then disunifying the symbol's shapes may be an answer.

A./
 Received on Wed Mar 16 2016 - 12:35:45 CDT

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