From ea2530788f41564207fb1b7c9ccec2fdf492590e Mon Sep 17 00:00:00 2001
From: lukasmartinelli <me@lukasmartinelli.ch>
Date: Fri, 28 Oct 2016 16:53:29 +0200
Subject: [PATCH] Filter out large rivers

---
 layers/water/mapping.yaml | 15 ++++++++++++---
 layers/water/water.sql    | 13 +++++++++----
 layers/water/water.yaml   |  2 +-
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/layers/water/mapping.yaml b/layers/water/mapping.yaml
index f9256cec..5e74ec64 100644
--- a/layers/water/mapping.yaml
+++ b/layers/water/mapping.yaml
@@ -1,15 +1,15 @@
 generalized_tables:
   water_polygon_gen3:
     source: water_polygon
-    sql_filter: area>15000000.0
+    sql_filter: area>15000000.0 AND waterway = ''
     tolerance: 350.0
   water_polygon_gen2:
     source: water_polygon
-    sql_filter: area>2000000
+    sql_filter: area>2000000 AND waterway = ''
     tolerance: 200.0
   water_polygon_gen1:
     source: water_polygon
-    sql_filter: area>500000
+    sql_filter: area>500000 AND waterway = ''
     tolerance: 100.0
 tables:
   water_polygon:
@@ -26,6 +26,15 @@ tables:
     - name: name_en
       key: name:en
       type: string
+    - name: natural
+      key: natural
+      type: string
+    - name: landuse
+      key: landuse
+      type: string
+    - name: waterway
+      key: waterway
+      type: string
     filters:
       exclude_tags:
       - [ "covered", "yes" ]
diff --git a/layers/water/water.sql b/layers/water/water.sql
index 7ce355a8..dab2aa95 100644
--- a/layers/water/water.sql
+++ b/layers/water/water.sql
@@ -1,3 +1,8 @@
+CREATE OR REPLACE FUNCTION water_class(waterway TEXT) RETURNS TEXT AS $$
+    SELECT CASE WHEN waterway='' THEN 'lake' ELSE 'river' END;
+$$ LANGUAGE SQL IMMUTABLE;
+
+
 CREATE OR REPLACE VIEW water_z0 AS (
     SELECT geom, 'ocean' AS class FROM ne_110m_ocean
     UNION ALL
@@ -51,19 +56,19 @@ CREATE OR REPLACE VIEW water_z9 AS (
 );
 
 CREATE OR REPLACE VIEW water_z11 AS (
-    SELECT geometry AS geom, 'lake' AS class FROM osm_water_polygon WHERE area > 40000
+    SELECT geometry AS geom, water_class(waterway) AS class FROM osm_water_polygon WHERE area > 40000
 );
 
 CREATE OR REPLACE VIEW water_z12 AS (
-    SELECT geometry AS geom, 'lake' AS class FROM osm_water_polygon WHERE area > 10000
+    SELECT geometry AS geom, water_class(waterway) AS class FROM osm_water_polygon WHERE area > 10000
 );
 
 CREATE OR REPLACE VIEW water_z13 AS (
-    SELECT geometry AS geom, 'lake' AS class FROM osm_water_polygon WHERE area > 5000
+    SELECT geometry AS geom, water_class(waterway) AS class FROM osm_water_polygon WHERE area > 5000
 );
 
 CREATE OR REPLACE VIEW water_z14 AS (
-    SELECT geometry AS geom, 'lake' AS class FROM osm_water_polygon
+    SELECT geometry AS geom, water_class(waterway) AS class FROM osm_water_polygon
 );
 
 CREATE OR REPLACE FUNCTION layer_water (bbox geometry, zoom_level int)
diff --git a/layers/water/water.yaml b/layers/water/water.yaml
index d4e315f9..69e52b96 100644
--- a/layers/water/water.yaml
+++ b/layers/water/water.yaml
@@ -1,7 +1,7 @@
 layer:
   id: "water"
   description: |
-      Water polygons and linestrings representing oceans, lakes and waterways.
+      Water polygons and linestrings representing oceans, lakes.
   buffer_size: 4
   datasource:
     query: (SELECT geom, class FROM layer_water(!bbox!, z(!scale_denominator!))) AS t