update.php - check file exists before deleting

[nominatim.git] / sql / country_grid.sql

diff --git a/sql/country_grid.sql b/sql/country_grid.sql
index 43fe4c2a17539952a676a5027cc62b78ca832626..08957cb75973bd541d5d8b0853c4db38528ff565 100644 (file)
--- a/sql/country_grid.sql
+++ b/sql/country_grid.sql
@@ -1,15 +1,33 @@
-drop table country_osm_grid2;
-create table country_osm_grid2 as select country_name.country_code,st_union(placex.geometry) as geometry from country_name,
+-- Script to build a calculated country grid from existing tables
+DROP TABLE IF EXISTS tmp_country_osm_grid;
+CREATE TABLE tmp_country_osm_grid as select country_name.country_code,st_union(placex.geometry) as geometry from country_name,
   placex
   where (lower(placex.country_code) = country_name.country_code)
-    and placex.rank_search < 16 and st_area(placex.geometry)>0 
+    and placex.rank_search < 16 and st_area(placex.geometry) > 0 
   group by country_name.country_code;
-alter table country_osm_grid2 add column area double precision;
-update country_osm_grid2 set area = st_area(geometry::geography);
-drop table country_osm_grid3;
-create table country_osm_grid3 as select country_code,area,quad_split_geometry(geometry,0.5,20) as geometry from country_osm_grid2;
-drop table country_osm_grid;
-alter table country_osm_grid3 rename to country_osm_grid;
-CREATE INDEX idx_country_osm_grid_geometry ON country_osm_grid USING GIST (geometry);
-update country_osm_grid set area = sum from (select country_code,sum(case when st_area(geometry::geography) = 'NaN' THEN 0 ELSE st_area(geometry::geography) END) 
- from country_osm_grid group by country_code) as x where x.country_code = country_osm_grid.country_code;
+ALTER TABLE tmp_country_osm_grid add column area double precision;
+UPDATE tmp_country_osm_grid set area = st_area(geometry::geography);
+
+-- compare old and new
+select country_code, round, round(log(area)) from (select distinct country_code,round(log(area)) from country_osm_grid order by country_code) as x 
+  left outer join tmp_country_osm_grid using (country_code) where area is null or round(log(area)) != round;
+
+DROP TABLE IF EXISTS new_country_osm_grid;
+CREATE TABLE new_country_osm_grid as select country_code,area,quad_split_geometry(geometry,0.5,20) as geometry from tmp_country_osm_grid;
+CREATE INDEX new_idx_country_osm_grid_geometry ON new_country_osm_grid USING GIST (geometry);
+
+-- Sometimes there are problems calculating area due to invalid data - optionally recalc
+UPDATE new_country_osm_grid set area = sum from (select country_code,sum(case when st_area(geometry::geography) = 'NaN' THEN 0 ELSE st_area(geometry::geography) END) 
+ from new_country_osm_grid group by country_code) as x where x.country_code = new_country_osm_grid.country_code;
+
+-- compare old and new
+select country_code, x.round, y.round from (select distinct country_code,round(log(area)) from country_osm_grid order by country_code) as x
+  left outer join (select distinct country_code,round(log(area)) from new_country_osm_grid order by country_code) as y
+    using (country_code) where x.round != y.round;
+
+-- Flip the new table in
+BEGIN;
+DROP TABLE IF EXISTS country_osm_grid;
+ALTER TABLE new_country_osm_grid rename to country_osm_grid;
+ALTER INDEX new_idx_country_osm_grid_geometry RENAME TO idx_country_osm_grid_geometry;
+COMMIT;