PostGIS  2.5.0dev-r@@SVN_REVISION@@
LWGEOM* lwgeom_snap ( const LWGEOM geom1,
const LWGEOM geom2,
double  tolerance 
)

Snap vertices and segments of a geometry to another using a given tolerance.

Parameters
geom1the geometry to snap
geom2the geometry to snap to
tolerancethe distance under which vertices and segments are snapped

Requires GEOS-3.3.0+

Definition at line 1527 of file liblwgeom/lwgeom_geos.c.

References error_if_srid_mismatch(), LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), lwerror(), LWGEOM2GEOS(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwnotice(), and LWGEOM::srid.

Referenced by _lwt_toposnap(), and ST_Snap().

1528 {
1529  int srid, is3d;
1530  GEOSGeometry *g1, *g2, *g3;
1531  LWGEOM* out;
1532 
1533  srid = geom1->srid;
1534  error_if_srid_mismatch(srid, (int)(geom2->srid));
1535 
1536  is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags)) ;
1537 
1538  initGEOS(lwnotice, lwgeom_geos_error);
1539 
1540  g1 = (GEOSGeometry *)LWGEOM2GEOS(geom1, 0);
1541  if ( 0 == g1 ) /* exception thrown at construction */
1542  {
1543  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
1544  return NULL;
1545  }
1546 
1547  g2 = (GEOSGeometry *)LWGEOM2GEOS(geom2, 0);
1548  if ( 0 == g2 ) /* exception thrown at construction */
1549  {
1550  lwerror("Second argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
1551  GEOSGeom_destroy(g1);
1552  return NULL;
1553  }
1554 
1555  g3 = GEOSSnap(g1, g2, tolerance);
1556  if (g3 == NULL)
1557  {
1558  GEOSGeom_destroy(g1);
1559  GEOSGeom_destroy(g2);
1560  lwerror("GEOSSnap: %s", lwgeom_geos_errmsg);
1561  return NULL;
1562  }
1563 
1564  GEOSGeom_destroy(g1);
1565  GEOSGeom_destroy(g2);
1566 
1567  GEOSSetSRID(g3, srid);
1568  out = GEOS2LWGEOM(g3, is3d);
1569  if (out == NULL)
1570  {
1571  GEOSGeom_destroy(g3);
1572  lwerror("GEOSSnap() threw an error (result LWGEOM geometry formation)!");
1573  return NULL;
1574  }
1575  GEOSGeom_destroy(g3);
1576 
1577  return out;
1578 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:177
uint8_t flags
Definition: liblwgeom.h:396
char lwgeom_geos_errmsg[LWGEOM_GEOS_ERRMSG_MAXSIZE]
void error_if_srid_mismatch(int srid1, int srid2)
Definition: lwutil.c:338
int32_t srid
Definition: liblwgeom.h:398
void lwgeom_geos_error(const char *fmt,...)
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, int autofix)
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, char want3d)
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190

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