Sub-national routes in Canada and refactor national network list (#1446)

This PR defines the set of routes in Canada which are equivalent in national importance to the US Interstate Highway System, and are therefore appropriate to render at zoom 4. This creates a sane, connected highway network at this zoom level across the USA and Canada.

This adds two additional network types for Canadian highways, ca-provincial for provincial-level roads, and ca-provincial-arterial for "highest importance" roads that are not part of the Trans-Canada highway but should be regarded as equivalent for low-zoom rendering purposes.

Additionally, this extracts out the country-specific network checks to a separate function in order to define "equivalent top-level networks" by country, providing a place to add additional national definitions as they're added by contributors.

layers/transportation/network_type.sql

@@ -15,12 +15,23 @@ $$
         WHEN undefined_object THEN
             CREATE TYPE route_network_type AS enum (
                 'us-interstate', 'us-highway', 'us-state',
-                'ca-transcanada',
+                'ca-transcanada', 'ca-provincial-arterial', 'ca-provincial',
                 'gb-motorway', 'gb-trunk'
                 );
     END
 $$;
 
+-- Top-level national route networks that should display at the lowest zooms
+CREATE OR REPLACE FUNCTION osm_national_network(network text) RETURNS boolean AS
+$$
+    SELECT network <> '' AND network IN (
+        -- Canada
+        'ca-transcanada', 'ca-provincial-arterial',
+        -- United States
+        'us-interstate');
+$$ LANGUAGE sql IMMUTABLE
+                PARALLEL SAFE;
+
 DO
 $$
     BEGIN

layers/transportation/update_route_member.sql

@@ -22,7 +22,7 @@ INSERT INTO osm_route_member (osm_id, member, ref, network)
 SELECT *
 FROM gbr_route_members_view;
 
-CREATE OR REPLACE FUNCTION osm_route_member_network_type(network text) RETURNS route_network_type AS
+CREATE OR REPLACE FUNCTION osm_route_member_network_type(network text, ref text) RETURNS route_network_type AS
 $$
 SELECT CASE
            WHEN network = 'US:I' THEN 'us-interstate'::route_network_type
@@ -30,6 +30,17 @@ SELECT CASE
            WHEN network LIKE 'US:__' THEN 'us-state'::route_network_type
            -- https://en.wikipedia.org/wiki/Trans-Canada_Highway
            WHEN network LIKE 'CA:transcanada%' THEN 'ca-transcanada'::route_network_type
+           WHEN network = 'CA:QC:A' THEN 'ca-provincial-arterial'::route_network_type
+           WHEN network = 'CA:ON:primary' THEN
+               CASE
+                   WHEN ref LIKE '4__' THEN 'ca-provincial-arterial'::route_network_type
+                   WHEN ref = 'QEW' THEN 'ca-provincial-arterial'::route_network_type
+                   ELSE 'ca-provincial-arterial'::route_network_type
+               END
+           WHEN network = 'CA:MB:PTH' AND ref = '75' THEN 'ca-provincial-arterial'::route_network_type
+           WHEN network = 'CA:AB:primary' AND ref IN ('2','3','4') THEN 'ca-provincial-arterial'::route_network_type
+           WHEN network = 'CA:BC' AND ref IN ('3','5','99') THEN 'ca-provincial-arterial'::route_network_type
+           WHEN network LIKE 'CA:__' OR network LIKE 'CA:__:%' THEN 'ca-provincial'::route_network_type
            WHEN network = 'omt-gb-motorway' THEN 'gb-motorway'::route_network_type
            WHEN network = 'omt-gb-trunk' THEN 'gb-trunk'::route_network_type
            END;
@@ -39,9 +50,9 @@ $$ LANGUAGE sql IMMUTABLE
 -- etldoc:  osm_route_member ->  osm_route_member
 -- see http://wiki.openstreetmap.org/wiki/Relation:route#Road_routes
 UPDATE osm_route_member
-SET network_type = osm_route_member_network_type(network)
+SET network_type = osm_route_member_network_type(network, ref)
 WHERE network != ''
-  AND network_type IS DISTINCT FROM osm_route_member_network_type(network)
+  AND network_type IS DISTINCT FROM osm_route_member_network_type(network, ref)
 ;
 
 CREATE OR REPLACE FUNCTION update_osm_route_member() RETURNS void AS
@@ -64,7 +75,7 @@ BEGIN
     SELECT
       id,
       osm_id,
-      osm_route_member_network_type(network) AS network_type,
+      osm_route_member_network_type(network, ref) AS network_type,
       DENSE_RANK() over (PARTITION BY member ORDER BY network_type, network, LENGTH(ref), ref) AS concurrency_index,
       CASE
            WHEN network IN ('iwn', 'nwn', 'rwn') THEN 1
@@ -80,7 +91,7 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql;
 
-CREATE INDEX IF NOT EXISTS osm_route_member_network_idx ON osm_route_member ("network");
+CREATE INDEX IF NOT EXISTS osm_route_member_network_idx ON osm_route_member ("network", "ref");
 CREATE INDEX IF NOT EXISTS osm_route_member_member_idx ON osm_route_member ("member");
 CREATE INDEX IF NOT EXISTS osm_route_member_name_idx ON osm_route_member ("name");
 CREATE INDEX IF NOT EXISTS osm_route_member_ref_idx ON osm_route_member ("ref");

layers/transportation/update_transportation_merge.sql

@@ -331,9 +331,7 @@ BEGIN
         (highway = 'motorway'
             OR construction = 'motorway'
             -- Allow trunk roads that are part of a nation's most important route network to show at z4
-            OR highway = 'trunk' AND
-                network <> '' AND
-                network IN ('ca-transcanada','us-interstate')
+            OR (highway = 'trunk' AND osm_national_network(network))
         ) AND
         ST_Length(geometry) > 500;
 
@@ -356,8 +354,8 @@ BEGIN
     FROM osm_transportation_merge_linestring_gen_z5
     WHERE
         (update_id IS NULL OR id = update_id) AND
+        osm_national_network(network) AND
         -- Current view: national-importance motorways and trunks
-        network IN ('ca-transcanada','us-interstate') AND
         ST_Length(geometry) > 1000;
 END;
 $$ LANGUAGE plpgsql;

layers/transportation_name/transportation_name.yaml

@@ -28,6 +28,8 @@ layer:
       - us-highway
       - us-state
       - ca-transcanada
+      - ca-provincial-arterial
+      - ca-provincial
       - gb-motorway
       - gb-trunk
       - road (default)