From: Paul Ramsey <pramsey@cleverelephant.ca>
Date: Tue, 3 Jan 2012 22:07:34 +0000 (+0000)
Subject: Make ST_Azimuth(p1, p1) return NULL and make ST_Project(p1, 0, NULL) return p1.
X-Git-Tag: 2.0.0alpha1~213
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=343f318428ed090d0311a7032ae1973c3ddd6166;p=postgis

Make ST_Azimuth(p1, p1) return NULL and make ST_Project(p1, 0, NULL) return p1.


git-svn-id: http://svn.osgeo.org/postgis/trunk@8662 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/liblwgeom/lwgeodetic.c b/liblwgeom/lwgeodetic.c
index cd7918b0b..83d7db663 100644
--- a/liblwgeom/lwgeodetic.c
+++ b/liblwgeom/lwgeodetic.c
@@ -1849,8 +1849,7 @@ LWPOINT* lwgeom_project_spheroid(const LWPOINT *r, const SPHEROID *spheroid, dou
 * @param r - location of first point.
 * @param s - location of second point.
 * @param spheroid - spheroid definition.
-* @param azimuth - azimuth in radians.
-* @return 
+* @return azimuth - azimuth in radians. 
 * 
 */
 double lwgeom_azumith_spheroid(const LWPOINT *r, const LWPOINT *s, const SPHEROID *spheroid)
@@ -1868,10 +1867,10 @@ double lwgeom_azumith_spheroid(const LWPOINT *r, const LWPOINT *s, const SPHEROI
 	y2 = lwpoint_get_y(s);
 	geographic_point_init(x2, y2, &g2);
 	
-	/* Same point, return a standard azimuth instead of NULL or NaN */
+	/* Same point, return NaN */
 	if ( FP_EQUALS(x1, x2) && FP_EQUALS(y1, y2) )
 	{
-		return 0.0;
+		return NAN;
 	}
 	
 	/* Do the direction calculation */
diff --git a/postgis/geography.sql.in.c b/postgis/geography.sql.in.c
index 6ee506879..d87d6b620 100644
--- a/postgis/geography.sql.in.c
+++ b/postgis/geography.sql.in.c
@@ -575,7 +575,7 @@ CREATE OR REPLACE FUNCTION ST_Length(text)
 CREATE OR REPLACE FUNCTION ST_Project(geog geography, distance float8, azimuth float8)
 	RETURNS geography
 	AS 'MODULE_PATHNAME','geography_project'
-	LANGUAGE 'C' IMMUTABLE STRICT
+	LANGUAGE 'C' IMMUTABLE
 	COST 100;
 
 -- Availability: 2.0.0
diff --git a/postgis/geography_measurement.c b/postgis/geography_measurement.c
index a7a463c03..9a6383b14 100644
--- a/postgis/geography_measurement.c
+++ b/postgis/geography_measurement.c
@@ -624,7 +624,12 @@ Datum geography_project(PG_FUNCTION_ARGS)
 		elog(ERROR, "ST_Project(geography) is only valid for point inputs");
 		PG_RETURN_NULL();
     }
+
+	/* Return NULL on NULL distance */
+	if ( PG_ARGISNULL(1) )
+		PG_RETURN_NULL();
 	
+	distance = PG_GETARG_FLOAT8(1); /* Distance in Meters */
 	lwgeom = lwgeom_from_gserialized(g);
 
 	/* EMPTY things cannot be projected from */
@@ -635,13 +640,20 @@ Datum geography_project(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 	}
 	
-	/* Read the other parameters */
-	distance = PG_GETARG_FLOAT8(1); /* Meters */
-	azimuth = PG_GETARG_FLOAT8(2); /* Radians */
+	if ( PG_ARGISNULL(2) )
+		azimuth = 0.0;
+	else
+		azimuth = PG_GETARG_FLOAT8(2); /* Azimuth in Radians */
 
 	/* Initialize spheroid */
 	spheroid_init(&s, WGS84_MAJOR_AXIS, WGS84_MINOR_AXIS);
 
+	/* Handle the zero distance case */
+	if( FP_EQUALS(distance, 0.0) )
+	{
+		PG_RETURN_POINTER(g);
+	}
+
 	/* Calculate the length */
 	lwp_projected = lwgeom_project_spheroid(lwgeom_as_lwpoint(lwgeom), &s, distance, azimuth);
 
@@ -715,6 +727,13 @@ Datum geography_azimuth(PG_FUNCTION_ARGS)
 
 	PG_FREE_IF_COPY(g1, 0);
 	PG_FREE_IF_COPY(g2, 1);
+
+	/* Return NULL for unknown (same point) azimuth */
+	if( isnan(azimuth) )
+	{
+		PG_RETURN_NULL();		
+	}
+
 	PG_RETURN_FLOAT8(azimuth);
 }
 
diff --git a/postgis/lwgeom_functions_basic.c b/postgis/lwgeom_functions_basic.c
index 62e971d53..0024c12a0 100644
--- a/postgis/lwgeom_functions_basic.c
+++ b/postgis/lwgeom_functions_basic.c
@@ -2355,7 +2355,7 @@ Datum LWGEOM_azimuth(PG_FUNCTION_ARGS)
 	/* Standard return value for equality case */
 	if ( FP_EQUALS(p1.x, p2.x) && FP_EQUALS(p1.y, p2.y) )
 	{
-		PG_RETURN_FLOAT8(0.0);
+		PG_RETURN_NULL();
 	}
 
 	/* Compute azimuth */