From: Paul Ramsey <pramsey@cleverelephant.ca>
Date: Sat, 8 Mar 2014 00:45:32 +0000 (+0000)
Subject: #2636, Regress ST_Distance_Sphere between 2.1.2dev and 2.0.4 with 2D
X-Git-Tag: 2.2.0rc1~1204
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=44cf4543aa2f8e4ed52b77120bf74f712217f300;p=postgis

#2636, Regress ST_Distance_Sphere between 2.1.2dev and 2.0.4 with 2D


git-svn-id: http://svn.osgeo.org/postgis/trunk@12307 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/liblwgeom/lwgeodetic.c b/liblwgeom/lwgeodetic.c
index 214d64db6..be5a9255b 100644
--- a/liblwgeom/lwgeodetic.c
+++ b/liblwgeom/lwgeodetic.c
@@ -1815,7 +1815,13 @@ static double ptarray_distance_spheroid(const POINTARRAY *pa1, const POINTARRAY
 			e1.start = e1.end;
 		}
 
-		return spheroid_distance(&g1, &nearest2, s);
+		/* On sphere, return answer */
+		if ( use_sphere )
+			return distance;
+		/* On spheroid, calculate final answer based on closest approach */
+		else
+			return spheroid_distance(&g1, &nearest2, s);
+
 	}
 
 	/* Initialize start of line 1 */
diff --git a/liblwgeom/lwgeodetic_tree.c b/liblwgeom/lwgeodetic_tree.c
index 19da35aed..383f6ac75 100644
--- a/liblwgeom/lwgeodetic_tree.c
+++ b/liblwgeom/lwgeodetic_tree.c
@@ -522,13 +522,19 @@ circ_tree_distance_tree(const CIRC_NODE* n1, const CIRC_NODE* n2, const SPHEROID
 	double min_dist = MAXFLOAT;
 	double max_dist = MAXFLOAT;
 	GEOGRAPHIC_POINT closest1, closest2;
-	double distance2;
 	double threshold_radians = threshold / spheroid->radius;
 	
 	circ_tree_distance_tree_internal(n1, n2, threshold_radians, &min_dist, &max_dist, &closest1, &closest2);
-	distance2 = spheroid_distance(&closest1, &closest2, spheroid);
 
-	return distance2;
+	/* Spherical case */
+	if ( spheroid->a == spheroid->b )
+	{
+		return spheroid->radius * sphere_distance(&closest1, &closest2);
+	}
+	else
+	{
+		return spheroid_distance(&closest1, &closest2, spheroid);		
+	}
 }
 
 static double