Merge pull request #3575 from lonvia/improve-centroid

[nominatim.git] / lib-sql / functions / utils.sql

diff --git a/lib-sql/functions/utils.sql b/lib-sql/functions/utils.sql
index f8b365c582cce8cae569564bc9655335b8b69e1d..1445be5435624ef55c129f2cff2a037827e7fc05 100644 (file)
--- a/lib-sql/functions/utils.sql
+++ b/lib-sql/functions/utils.sql
@@ -7,20 +7,37 @@
 
 -- Assorted helper functions for the triggers.
 
 
 -- Assorted helper functions for the triggers.
 

-CREATE OR REPLACE FUNCTION geometry_sector(partition INTEGER, place geometry)
-  RETURNS INTEGER
+CREATE OR REPLACE FUNCTION get_center_point(place GEOMETRY)
+  RETURNS GEOMETRY

   AS $$
 DECLARE
   AS $$
 DECLARE

-  NEWgeometry geometry;
+  geom_type TEXT;
+BEGIN
+  geom_type := ST_GeometryType(place);
+  IF geom_type = ' ST_Point' THEN
+    RETURN place;
+  END IF;
+  IF geom_type = 'ST_LineString' THEN
+    RETURN ST_LineInterpolatePoint(place, 0.5);
+  END IF;
+
+  RETURN ST_PointOnSurface(place);
+END;
+$$
+LANGUAGE plpgsql IMMUTABLE;
+
+
+CREATE OR REPLACE FUNCTION geometry_sector(partition INTEGER, place GEOMETRY)
+  RETURNS INTEGER
+  AS $$

 BEGIN
 BEGIN

---  RAISE WARNING '%',place;
-  NEWgeometry := ST_PointOnSurface(place);
-  RETURN (partition*1000000) + (500-ST_X(NEWgeometry)::integer)*1000 + (500-ST_Y(NEWgeometry)::integer);
+  RETURN (partition*1000000) + (500-ST_X(place)::INTEGER)*1000 + (500-ST_Y(place)::INTEGER);

 END;
 $$
 LANGUAGE plpgsql IMMUTABLE;
 
 
 END;
 $$
 LANGUAGE plpgsql IMMUTABLE;
 
 

+

 CREATE OR REPLACE FUNCTION array_merge(a INTEGER[], b INTEGER[])
   RETURNS INTEGER[]
   AS $$
 CREATE OR REPLACE FUNCTION array_merge(a INTEGER[], b INTEGER[])
   RETURNS INTEGER[]
   AS $$


@@ -158,24 +175,47 @@ $$
 LANGUAGE plpgsql STABLE;
 
 
 LANGUAGE plpgsql STABLE;
 
 

-CREATE OR REPLACE FUNCTION get_country_code(place geometry)
+CREATE OR REPLACE FUNCTION get_country_code(place_centre geometry)

   RETURNS TEXT
   AS $$
 DECLARE
   RETURNS TEXT
   AS $$
 DECLARE

-  place_centre GEOMETRY;

   nearcountry RECORD;
   nearcountry RECORD;

+  countries TEXT[];

 BEGIN
 BEGIN

-  place_centre := ST_PointOnSurface(place);
-

 -- RAISE WARNING 'get_country_code, start: %', ST_AsText(place_centre);
 
   -- Try for a OSM polygon
 -- RAISE WARNING 'get_country_code, start: %', ST_AsText(place_centre);
 
   -- Try for a OSM polygon

-  FOR nearcountry IN
-    SELECT country_code from location_area_country
-    WHERE country_code is not null and st_covers(geometry, place_centre) limit 1
-  LOOP
-    RETURN nearcountry.country_code;
-  END LOOP;
+  SELECT array_agg(country_code) FROM location_area_country
+    WHERE country_code is not null and st_covers(geometry, place_centre)
+    INTO countries;
+
+  IF array_length(countries, 1) = 1 THEN
+    RETURN countries[1];
+  END IF;
+
+  IF array_length(countries, 1) > 1 THEN
+    -- more than one country found, confirm against the fallback data what to choose
+    FOR nearcountry IN
+        SELECT country_code FROM country_osm_grid
+          WHERE ST_Covers(geometry, place_centre) AND country_code = ANY(countries)
+          ORDER BY area ASC
+    LOOP
+        RETURN nearcountry.country_code;
+    END LOOP;
+    -- Still nothing? Choose the country code with the smallest partition number.
+    -- And failing that, just go by the alphabet.
+    FOR nearcountry IN
+        SELECT cc,
+               (SELECT partition FROM country_name WHERE country_code = cc) as partition
+        FROM unnest(countries) cc
+        ORDER BY partition, cc
+    LOOP
+        RETURN nearcountry.cc;
+    END LOOP;
+
+    -- Should never be reached.
+    RETURN countries[1];
+  END IF;

 
 -- RAISE WARNING 'osm fallback: %', ST_AsText(place_centre);
 
 
 -- RAISE WARNING 'osm fallback: %', ST_AsText(place_centre);