Highway Ref tags with Farsi numerals تگ رف بزرگراه با مقداررقومی فارسی

Hi, one of OSMers in Iran suggested “Farsi numerals for highway Ref tags” which brings up the question of "how we’re going to tag both Farsi and English values, like in names we have name=* which gets Farsi value and name:en=* that gets English transliteration (not translation) but I didn’t see the same syntax in Ref tags, what do you think is the best way to do this?
سلام، یکی از او اس ام کاران در ایران، استفاده از تگ رف بزرگراه با مقداررقومی فارسی را توصیه نمودند، که این سوال را پیش میآورد که چگونه میتوانیم هم تگ رف با مقداررقومی فارسی داشته باشیم و هم معادل انگلیسی آن را، همانگونه که برای تگ نام،
را با مقدار فارسی و
را با مقدار معادل انگلیسی آن داریم (نه ترجمه آن را)، امّا من چنین قاعده نگارشی برای تگ رف ندیدم. شما فکر میکنید که بهترین راه برای انجام اینکار چیست؟

Hello all!
As we know there is no ref:fa/ref:en tag on OSM so I think first of all we must ask “why?” and then we must see if there is any possible to add these tags for OSM or not. till then we can do nothing or do something like insert Persian value by ref:fa next to the ref: or insert English value by ref:en next to the ref:.

سلام به همه! همونطور که ما میدونیم تگهای
ref:fa و ref:en
در او اس ام تعریف نشدن پس بنظر من ما اول باید ببینیم چرا تعریف نشدن و بعد ببینیم که آیا امکان اضافه کردن این تگها برای او اس ام وجود داره یا نه
تا اون زمان ما میتونیم به چیزی دست نزنیم و یا مثلاً تگ
رو با مقدار فارسی در کنار تگ
با مقدار انگلیسی اضافه کنیم و یا برعکس تگ
با مقدار انگلیسی رو در کنار تک
با مقدار فارسی اضافه کنیم.

Looks good to me, just to clarify, we have both Farsi and English Refs on the road signs in Iran.
بنظر من خوبه، فقط برای شفاف سازی، ما هر دو رف فارسی و انگلیسی رو روی تابلو جاده ها داریم در ایران

We need to take good care of semantics here:

I am emphasizing this because there is no such thing as "English numbers". This rules out the misleading - and I would even say wrong in the Iranian context - proposed use of **ref:en** as a tag. It would make sense if reference numbers included English words in Latin script for example, but all road reference numbers in Iran are numerals.

Let’s look at ref:fa as well: I would argue this is a misleading tag as well, since this would be the reference number in Persian language, while what is meant is actually the Persian script. ISO 15924 is the international standard to encode script names. Interestingly enough it doesn’t contain an entry for the Persian script, so there’s no option for a somewhat more fitting ref:fa-Pers (NB: I just made up “Pers” as a script ISO code. It doesn’t currently exist). See for reference the usage of name:ko-Latn meaning "Korean language romanized using the Latin Script and how it’s also applied as name:ja-Latn, name:ru-Latn or name:th-Latn.

So how can we move forward then? I’d suggest we make use from the fact that both numeral systems are representations of the same numeric value though. And road signage in Iran is using both numerals at the same time, see examples of road numbers signs in the List of roads and highways in Iran. So I actually think we don’t need to introduce and add any additional reference tagging. There is a direct 1-to-1 mapping of numerals as following:
0 => ۰
1 => ۱
2 => ۲
3 => ۳
4 => ۴
5 => ۵
6 => ۶
7 => ۷
8 => ۸
9 => ۹
So any application building upon OpenStreetMap data in Iran can easily pre-process that data and convert all road reference numbers to use Eastern Arabic Numerals via a simple direct replacement. This can both be applied to a Persian localized Garmin map during the data processing or in an Iranian map style when creating road shields.

International examples:
I reviewed various countries that use non-latin scripts for their primary language:

  • Oman seems to be the closest to Iran in that they use both Western and Arabic Numerals together on road signs.. But in OpenStreetMap everything seems to be tagged with only the Western Arabic Numerals in ref=…

  • The United Arab Emirates uses E and إ on the sign with the numeral written in Western Arabic Script, e.g. E 44

  • Similarly Qatar uses Q and ق on the sign with the numeral written in Western Arabic Script

  • Saudi Arabia is a bit inconclusive as some road signs seem to use a variant of Eastern Arabic Numerals. Google Maps renders all road signs with Western Arabic Numerals (at least when accessed from Europe).

  • Even the Arab Mashreq International Road network designation uses Western Arabic Numerals

  • Japan, South Korea, China and Thailand all use Western Arabic numerals for road numbers.

So in summary there seems to be a consensus in OpenStreetMap data towards using Western Arabic Numerals in the ref=... tag.

With all that information reviewed my proposal is to continue to tag road reference numbers in Iran as Western Arabic Numerals (0123456789) in the ref=… tag.

Code references: