Bind ST_LocateAlong() to the new LRS function that supports offsets.

git-svn-id: http://svn.osgeo.org/postgis/trunk@8757 b70326c6-7e19-0410-871a-916f4a2858ee

liblwgeom/lwlinearreferencing.c

@@ -154,13 +154,29 @@ lwmline_locate_along(const LWMLINE *lwmline, double m, double offset)
 	return lwmpoint;
 }
 
+static LWPOINT*
+lwpoint_locate_along(const LWPOINT *lwpoint, double m, double offset)
+{
+	LWGEOM *lwg = lwpoint_as_lwgeom(lwpoint);
+	double point_m = lwpoint_get_m(lwpoint);
+	if ( FP_EQUALS(m, point_m) )
+		return lwpoint_clone(lwpoint);
+	else
+		return lwpoint_construct_empty(lwgeom_get_srid(lwg), lwgeom_has_z(lwg), lwgeom_has_m(lwg));
+}
+
 LWGEOM*
 lwgeom_locate_along(const LWGEOM *lwin, double m, double offset)
 {
 	if ( ! lwin ) return NULL;
+
+	if ( ! lwgeom_has_m(lwin) )
+		lwerror("Input geometry does not have a measure dimension");	
 	
 	switch (lwin->type)
 	{
+	case POINTTYPE:
+		return (LWGEOM*)lwpoint_locate_along((LWPOINT*)lwin, m, offset);
 	case LINETYPE:
 		return (LWGEOM*)lwline_locate_along((LWLINE*)lwin, m, offset);
 	case MULTILINETYPE:

postgis/lwgeom_functions_lrs.c

@@ -18,7 +18,6 @@
 
 
 Datum LWGEOM_locate_between_m(PG_FUNCTION_ARGS);
-Datum ST_AddMeasure(PG_FUNCTION_ARGS);
 
 typedef struct
 {
@@ -520,11 +519,11 @@ Datum LWGEOM_locate_between_m(PG_FUNCTION_ARGS)
 
 
 /*
-* CREATE OR REPLACE FUNCTION ST_AddMeasure(geometry, float8, float8)
-* RETURNS geometry
-* AS '$libdir/postgis-1.5', 'ST_AddMeasure'
-* LANGUAGE 'C' IMMUTABLE STRICT;
+* Add a measure dimension to a line, interpolating linearly from the
+* start value to the end value.
+* ST_AddMeasure(Geometry, StartMeasure, EndMeasure) returns Geometry
 */
+Datum ST_AddMeasure(PG_FUNCTION_ARGS);
 PG_FUNCTION_INFO_V1(ST_AddMeasure);
 Datum ST_AddMeasure(PG_FUNCTION_ARGS)
 {
@@ -554,7 +553,37 @@ Datum ST_AddMeasure(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 
 	gout = geometry_serialize(lwout);
-	lwgeom_release(lwout);
+	lwgeom_free(lwout);
+
+	PG_RETURN_POINTER(gout);
+}
+
+
+/*
+* Locate a point along a feature based on a measure value.
+* ST_LocateAlong(Geometry, Measure, [Offset]) returns Geometry
+*/
+Datum ST_LocateAlong(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(ST_LocateAlong);
+Datum ST_LocateAlong(PG_FUNCTION_ARGS)
+{
+	GSERIALIZED *gin = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	GSERIALIZED *gout;
+	LWGEOM *lwin = NULL, *lwout = NULL;
+	double measure = PG_GETARG_FLOAT8(1);
+	double offset = PG_GETARG_FLOAT8(2);;
+	
+	lwnotice("offset %g",offset);
+	lwin = lwgeom_from_gserialized(gin);
+	lwout = lwgeom_locate_along(lwin, measure, offset);
+	lwgeom_free(lwin);
+	PG_FREE_IF_COPY(gin, 0);
+	
+	if ( ! lwout )
+		PG_RETURN_NULL();
+	
+	gout = geometry_serialize(lwout);
+	lwgeom_free(lwout);
 
 	PG_RETURN_POINTER(gout);
 }

postgis/postgis.sql.in.c

@@ -4512,27 +4512,17 @@ CREATE OR REPLACE FUNCTION ST_WKBToSQL(bytea)
 ---
 -- Linear referencing functions
 ---
-CREATE OR REPLACE FUNCTION ST_LocateBetween(geometry, float8, float8)
+CREATE OR REPLACE FUNCTION ST_LocateBetween(Geometry geometry, Measure1 float8, Measure2 float8, Offsets float8 default 0.0)
 	RETURNS geometry
 	AS 'MODULE_PATHNAME', 'LWGEOM_locate_between_m'
 	LANGUAGE 'C' IMMUTABLE STRICT;
 	
-CREATE OR REPLACE FUNCTION ST_LocateAlong(geometry, float8)
+CREATE OR REPLACE FUNCTION ST_LocateAlong(Geometry geometry, Measure float8, Offsets float8 default 0.0)
 	RETURNS geometry
-	AS $$ SELECT ST_LocateBetween($1, $2, $2) $$
-	LANGUAGE 'sql' IMMUTABLE STRICT;
+	AS 'MODULE_PATHNAME', 'ST_LocateAlong'
+	LANGUAGE 'C' IMMUTABLE STRICT;
 
--- LRS with offset parameter
-CREATE OR REPLACE FUNCTION ST_LocateBetween(geometry, float8, float8, float8)
-	RETURNS geometry
-	AS 'MODULE_PATHNAME', 'LWGEOM_locate_between_m'
-	LANGUAGE 'C' IMMUTABLE STRICT;
 	
--- LRS with offset parameter
-CREATE OR REPLACE FUNCTION ST_LocateAlong(geometry, float8, float8)
-	RETURNS geometry
-	AS $$ SELECT ST_LocateBetween($1, $2, $2) $$
-	LANGUAGE 'sql' IMMUTABLE STRICT;
 ---------------------------------------------------------------
 -- END
 ---------------------------------------------------------------