From b9063c49f338f9fef6edc1f6e13e47d34a52f444 Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Thu, 26 Apr 2012 16:30:18 +0000
Subject: [PATCH] Give ST_Azimuth a chance with close but distinct points
 (#1791)

git-svn-id: http://svn.osgeo.org/postgis/trunk@9682 b70326c6-7e19-0410-871a-916f4a2858ee
---
 NEWS                             | 1 +
 postgis/lwgeom_functions_basic.c | 2 +-
 regress/tickets.sql              | 7 +++++++
 regress/tickets_expected         | 1 +
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 4b27a5fd6..793e362fb 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ PostGIS 2.0.1
 
 * Bug Fixes *
 
+  - #1791, fix ST_Azimuth with very close but distinct points.
   - #1775, ST_ChangeEdgeGeom collision detection with 2-vertex target.
   - #1776, fix ST_SymDifference(empty, geom) to return geom.
   - #1708, improve restore of PosgreSQL 9.1 backups.
diff --git a/postgis/lwgeom_functions_basic.c b/postgis/lwgeom_functions_basic.c
index 796675fc6..5a3398f17 100644
--- a/postgis/lwgeom_functions_basic.c
+++ b/postgis/lwgeom_functions_basic.c
@@ -2376,7 +2376,7 @@ Datum LWGEOM_azimuth(PG_FUNCTION_ARGS)
 	PG_FREE_IF_COPY(geom, 1);
 
 	/* Standard return value for equality case */
-	if ( FP_EQUALS(p1.x, p2.x) && FP_EQUALS(p1.y, p2.y) )
+	if ( (p1.x == p2.x) && (p1.y == p2.y) )
 	{
 		PG_RETURN_NULL();
 	}
diff --git a/regress/tickets.sql b/regress/tickets.sql
index 879e45f97..c2e23050f 100644
--- a/regress/tickets.sql
+++ b/regress/tickets.sql
@@ -670,5 +670,12 @@ SELECT '#1776',
  ST_AsText(ST_SymDifference(A,B)), ST_AsText(ST_SymDifference(B, A))
 FROM inp;
 
+-- #1791 --
+with inp as ( SELECT
+ '010100000000000000004065C0041AD965BE5554C0'::geometry as a,
+ '010100000001000000004065C0041AD965BE5554C0'::geometry as b
+) SELECT '#1791', round(ST_Azimuth(a,b)*10)/10 from inp;
+
+
 -- Clean up
 DELETE FROM spatial_ref_sys;
diff --git a/regress/tickets_expected b/regress/tickets_expected
index 24060f7c8..a70f86f03 100644
--- a/regress/tickets_expected
+++ b/regress/tickets_expected
@@ -218,3 +218,4 @@ NOTICE:  SRID value -1 converted to the officially unknown SRID value 0
 #1734.1|1026
 #1755|01010000A0E6100000000000000040554000000000008041400000000000000000
 #1776|POLYGON((0 0,10 0,10 10,0 0))|POLYGON((0 0,10 0,10 10,0 0))
+#1791|4.7
-- 
2.40.0