[OSM-dev] Rendering of long street names for short streets

[Arne Goetje]

Hi list,

in Taiwan we have the situation, that street names may be too long to be
rendered on the map. In addition, we'd like to keep the map bilingual
(Chinese, Romanized/English), which makes the names rendered on the map
even longer. How can we give the renderer some hints how to abbreviate
the street names properly in different zoom levels?

Would it be possible to specify multiple alternative entries in the
'name' tag and the renderer picks whatever fits onto the map?

For example:
A very common naming scheme for small alleys is to number them according
to their location on the main road. When a lane/alley is located between
house numbers 8 and 12, it would carry the number 10.
The naming scheme is:
 * Main Road (路/街/道) -- optionally with Section (段)
  * Chinese: 介壽路二段
  * Full romanized/English name: Jieshou Road Section 2 (or: Section 2
Jieshou Road)
  * Abbr.: Jieshou Rd. Sec. 2 (or: Sec. 2 Jieshou Rd.)
 * Lane (巷)
  * Full Chinese name: 介壽路二段325巷
  * Full romanized/English name: Lane 325, Jieshou Road Section 2
  * Chinese abbr.: 325巷 (rendered next to the associated main road on
Chinese maps)
  * Romanized/English abbr.: Ln. 325, Jieshou Rd. Sec. 2
  * Further abbrevation: Ln. 325 (rendered next to the associated main road)
 * Alley (弄)
  * Full Chinese name: 介壽路二段325巷1弄
  * Full romanized/English name: Alley 1, Lane 325, Jieshou Road Section 2
  * Chinese abbr.: 325巷1弄 (or: 1弄 rendered next to the associated lane)
  * Romanized/English abbr.: Aly. 1, Ln. 325, Jieshou Rd. Sec. 2
  * Further abbrevation.: Aly. 1, Ln. 325 (or: Aly. 1 rendered next to
the associated lane)
 * Cross-Alley (衖)
  * Full Chinese name: 介壽路二段325巷1弄1衖
  * Full romanized/English name: Alley 1-1, Lane 325, Jieshou Road Section 2
  * Chinese abbr.: 325巷1弄1衖 (or: 1弄1衖, or: 1衖)
  * Romanized/English abbr.: Aly. 1-1, Ln. 325, Jieshou Rd. Sec. 2
  * Further abbr.: Aly. 1-1, Ln. 325 (or: Aly. 1-1)

Now: a user would search for either the full Chinese name, or the most
complete romanized/English abbreviation, but not the full
romanized/English name (nobody uses that one).
So, the database and routing engine would need to know those entries:
 * Chinese: 介壽路二段325巷1弄1衖 （actually it would need the full
address, which would include city and county, except for bigger cities,
there the county is omitted)
 * Romanized/English: Aly. 1-1, Ln. 325, Jieshou Rd. Sec. 2

On the map however, the lanes and alleys are usually quite short. We do
prefer to render the names bilingual, i.e. Chinese name
(romanized/English name) -> 介壽路二段325巷1弄1衖 (Aly. 1-1, Ln. 325,
Jieshou Rd. Sec. 2), but fall back to Chinese only if the alleys are
even too short for the abbreviations below (Sometimes alleys are just 20
Meters long).
So, it would be nice if we could tag the roads with a list of
alternatives for the renderer to pick from in order to render the street
name according to the zoom level.
 e.g.:
  * 介壽路二段325巷1弄1衖 (Aly. 1-1, Ln. 325, Jieshou Rd. Sec. 2)
  * 325巷1弄1衖 (Aly. 1-1, Ln. 325)
  * 1弄1衖 (Aly. 1-1)
  * 325巷1弄1衖
  * 1弄1衖
  * 1衖

For the rendering options: just put them all in the 'name' tag,
separated by ';' ?

For the rendering position, I was thinking: maybe this could be done
with relations?
E.g.: 介壽路二段325巷1弄1衖 is a member of 介壽路二段325巷1弄, which is
a member of 介壽路二段325巷, which is a member of 介壽路二段, which is a
member of 八德市 (city), which is a member of 桃園縣 (county).

If we would build up relations like that and also include the house
numbers, would we be able to find the house if we provide the full
address in one string (e.g. 桃園縣八德市介壽路二段325巷1弄1衖39號)? Or
would we need to tag each house with the full address individually?

How about postal codes? Also use relations for that? (E.g. a relation
for postal code 33444 would include all the roads, lanes, alleys and
houses)?

Would Mapnik/Osmarender be able to handle such constructs?

Cheers
Arne
-- 
Arne Götje (高盛華) <arne at linux.org.tw>
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