PostGIS  2.5.0beta2dev-r@@SVN_REVISION@@

◆ lwgeom_snap()

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 1321 of file liblwgeom/lwgeom_geos.c.

References AUTOFIX, LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), GEOS_FAIL, GEOS_FREE, GEOS_FREE_AND_FAIL, LWGEOM2GEOS(), lwgeom_geos_error(), lwnotice(), RESULT_SRID, and SRID_INVALID.

Referenced by _lwt_toposnap(), and ST_Snap().

1322 {
1323  LWGEOM* result;
1324  int32_t srid = RESULT_SRID(geom1, geom2);
1325  uint8_t is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags));
1326  GEOSGeometry *g1, *g2, *g3;
1327 
1328  if (srid == SRID_INVALID) return NULL;
1329 
1330  initGEOS(lwnotice, lwgeom_geos_error);
1331 
1332  if (!(g1 = LWGEOM2GEOS(geom1, AUTOFIX))) GEOS_FAIL();
1333  if (!(g2 = LWGEOM2GEOS(geom2, AUTOFIX))) GEOS_FREE_AND_FAIL(g1);
1334 
1335  g3 = GEOSSnap(g1, g2, tolerance);
1336 
1337  if (!g3) GEOS_FREE_AND_FAIL(g1, g2);
1338  GEOSSetSRID(g3, srid);
1339 
1340  if (!(result = GEOS2LWGEOM(g3, is3d)))
1341  GEOS_FREE_AND_FAIL(g1, g2, g3);
1342 
1343  GEOS_FREE(g1, g2, g3);
1344  return result;
1345 }
#define GEOS_FAIL()
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, uint8_t want3d)
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:177
uint8_t flags
Definition: liblwgeom.h:399
#define GEOS_FREE_AND_FAIL(...)
#define GEOS_FREE(...)
#define RESULT_SRID(...)
#define AUTOFIX
void lwgeom_geos_error(const char *fmt,...)
#define SRID_INVALID
Definition: liblwgeom.h:191
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, uint8_t autofix)
unsigned char uint8_t
Definition: uthash.h:79
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