Categorize regional & national public transit trains

[nvkelso]

In the transit layer, we just tossed in all route=train features. Let's characterize if it's a regional train or not so the styling and zoom ranges can be distinct.

• Related subway & light rail / Tram zoom changes: Adjust zoom ranges of subway, light rail & tram #472
• Related to funicular zoom changes: Add funicular & monorail to transit layer #588

UPDATE: Once we add the service property from the route relation, we can make the following selection: service IN ('high_speed', 'long_distance', 'international'). That set should have a min_zoom = 5, while the remainder should remain min_zoom = 6.

• Include service in transit.jinja layer selection SQL
• Update minimum zoom for "national" rail to 5 in the mz_calculate_transit_level SQL function.
• Do we need to update the GIST index in apply-planet_osm_line.sql?
• Connects with?: Add new transit layer features #469.

[nvkelso]

minimum zoom of national trains should change to 5, and regional trains should stay at 6

[nvkelso]

Related service tag discussion on OSM transit relations: #548 (comment)

[nvkelso]

From the discussion in #548:

Says @zerebubuth:

The transit layer currently contains the route / "line" relations, which cover the whole length of the route / named service / "line". The service attribute might be different from what you expect, especially if you're looking for short segments to drop. From my North America extract, here's a table of the count of features with distinct route and service values:

   route    |    service    |  num  
------------+---------------+-------
 train      | regional      | 13853
 train      | high_speed    |  6768
 train      | long_distance |  3092
 train      |               |  2347
 train      | commuter      |   218
 train      | international |    68
 train      | car           |    23
 train      | tourism       |     3

99% of the features are covered by service IN ('regional', 'high_speed', 'long_distance') OR service IS NULL.

[nvkelso]

Looks like there is a similar tag to service called passenger. TagInfo says, but those look to be rarely applied to route_relations.

One example is Amtrak California Zephyr.

• passenger=national
• service=long_distance

[nvkelso]

LGTM