From 8654c22c87affd439423be4f5b6b3e35b4850366 Mon Sep 17 00:00:00 2001
From: John Krauss <irving.krauss@gmail.com>
Date: Tue, 12 Jul 2016 14:06:43 -0400
Subject: [PATCH] handle area categories properly

---
 src/pg/sql/41_observatory_augmentation.sql | 42 +++++++++++++++-------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/pg/sql/41_observatory_augmentation.sql b/src/pg/sql/41_observatory_augmentation.sql
index 80d56d1..277cc00 100644
--- a/src/pg/sql/41_observatory_augmentation.sql
+++ b/src/pg/sql/41_observatory_augmentation.sql
@@ -457,19 +457,35 @@ BEGIN
          geom_geomref_colname, geom_colname, geom_table
     USING COALESCE(boundary_id, ''), category_id, COALESCE(time_span, '');
 
-  EXECUTE format(
-      'SELECT %I
-       FROM observatory.%I data, observatory.%I geom
-       WHERE data.%I = geom.%I
-         AND ST_WITHIN(%L, geom.%I) ',
-       colname,
-       data_table,
-       geom_table,
-       data_geomref_colname,
-       geom_geomref_colname,
-       geom,
-       geom_colname)
-  INTO category_val;
+  IF ST_GeometryType(geom) = 'ST_Point' THEN
+    EXECUTE format(
+        'SELECT %I
+         FROM observatory.%I data, observatory.%I geom
+         WHERE data.%I = geom.%I
+           AND ST_WITHIN(%L, geom.%I) ',
+         colname, data_table, geom_table, data_geomref_colname,
+         geom_geomref_colname, geom, geom_colname)
+    INTO category_val;
+  ELSE
+    -- favor the category with the most area
+    EXECUTE format(
+       'WITH _overlaps AS (
+          SELECT ST_Area(
+            ST_Intersection(%I, a.%I)
+          ) / ST_Area(a.%I) AS overlap_fraction, %I geomref
+          FROM observatory.%I as a
+          WHERE %I && a.%I,
+        SELECT %I category
+         FROM observatory.%I data
+         WHERE data.%I = geomref
+         GROUP BY category
+         ORDER BY SUM(overlap_fraction)
+        LIMIT 1',
+          geom, geom_colname, geom_colname, geom_geomref_colname,
+          geom_table, geom, geom_colname,
+          colname, data_table, data_geomref_colname)
+    INTO category_val;
+  END IF;
 
   RETURN category_val;