From: Regina Obe <lr@pcorp.us>
Date: Thu, 10 Nov 2016 04:07:45 +0000 (+0000)
Subject: Bug in geography ST_Segmentize
X-Git-Tag: 2.4.0alpha~220
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cc3437595e88eac7f20b0f3b780a3816cdc912c9;p=postgis

Bug in geography ST_Segmentize
Closes #3667 for PostGIS 2.4.0 (trunk)
Patch provided by Hugo Mercier (Oslandia)

git-svn-id: http://svn.osgeo.org/postgis/trunk@15223 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/liblwgeom/lwgeodetic.c b/liblwgeom/lwgeodetic.c
index cc1773408..b48a90868 100644
--- a/liblwgeom/lwgeodetic.c
+++ b/liblwgeom/lwgeodetic.c
@@ -949,6 +949,8 @@ double sphere_direction(const GEOGRAPHIC_POINT *s, const GEOGRAPHIC_POINT *e, do
 	f = (sin(e->lat) - sin(s->lat) * cos(d)) / (sin(d) * cos(s->lat));
 	if ( FP_EQUALS(f, 1.0) )
 		heading = 0.0;
+	else if ( FP_EQUALS(f, -1.0) )
+		heading = M_PI;
 	else if ( fabs(f) > 1.0 )
 	{
 		LWDEBUGF(4, "f = %g", f);
diff --git a/regress/geography.sql b/regress/geography.sql
index f79b22375..fc0358402 100644
--- a/regress/geography.sql
+++ b/regress/geography.sql
@@ -117,6 +117,10 @@ SELECT 'segmentize_geography', max(st_distance(d1.geom::geography, d2.geom::geog
 -- Check that st_segmentize creates segments on the geodesic path
 SELECT 'segmentize_geography2', st_dwithin(st_pointn(st_segmentize('linestring(1 47,-64 47)'::geography, 3000000)::geometry, 2), 'SRID=4326;POINT(-31.5 51.81)'::geometry, 0.01);
 
+-- #bug 3667
+SELECT 'segmentize_geography_3667', abs(ST_Length(geog) - ST_Length(ST_Segmentize(geog, 30000))) < 0.00001
+  FROM (SELECT ST_GeographyFromText('LINESTRING(38.769917 10.780694, 38.769917 9.106194)') As geog) AS f;
+
 -- Clean up spatial_ref_sys
 DELETE FROM spatial_ref_sys WHERE srid IN (4269,4326);
 
diff --git a/regress/geography_expected b/regress/geography_expected
index db6e8a424..cdbb99ae2 100644
--- a/regress/geography_expected
+++ b/regress/geography_expected
@@ -29,3 +29,4 @@ geog_precision_pazafir|0|0
 #2422|1|1068|f|f|1400.230|1396.816|1400.230|1400.230
 segmentize_geography|49789
 segmentize_geography2|t
+segmentize_geography_3667|t