PostGIS  2.3.8dev-r@@SVN_REVISION@@

◆ lwgeom_buildarea()

LWGEOM* lwgeom_buildarea ( const LWGEOM geom)

Take a geometry and return an areal geometry (Polygon or MultiPolygon).

Actually a wrapper around GEOSpolygonize, transforming the resulting collection into a valid polygon Geometry.

Definition at line 1382 of file liblwgeom/lwgeom_geos.c.

References LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), LWDEBUG, LWDEBUGF, lwerror(), LWGEOM2GEOS(), LWGEOM_GEOS_buildArea(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), lwpoly_construct_empty(), and LWGEOM::srid.

Referenced by _lwt_FaceByEdges(), buildarea1(), buildarea2(), buildarea3(), buildarea4(), buildarea4b(), buildarea5(), buildarea6(), buildarea7(), and ST_BuildArea().

1383 {
1384  GEOSGeometry* geos_in;
1385  GEOSGeometry* geos_out;
1386  LWGEOM* geom_out;
1387  int SRID = (int)(geom->srid);
1388  int is3d = FLAGS_GET_Z(geom->flags);
1389 
1390  /* Can't build an area from an empty! */
1391  if ( lwgeom_is_empty(geom) )
1392  {
1393  return (LWGEOM*)lwpoly_construct_empty(SRID, is3d, 0);
1394  }
1395 
1396  LWDEBUG(3, "buildarea called");
1397 
1398  LWDEBUGF(3, "ST_BuildArea got geom @ %p", geom);
1399 
1400  initGEOS(lwnotice, lwgeom_geos_error);
1401 
1402  geos_in = LWGEOM2GEOS(geom, 0);
1403 
1404  if ( 0 == geos_in ) /* exception thrown at construction */
1405  {
1406  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
1407  return NULL;
1408  }
1409  geos_out = LWGEOM_GEOS_buildArea(geos_in);
1410  GEOSGeom_destroy(geos_in);
1411 
1412  if ( ! geos_out ) /* exception thrown.. */
1413  {
1414  lwerror("LWGEOM_GEOS_buildArea: %s", lwgeom_geos_errmsg);
1415  return NULL;
1416  }
1417 
1418  /* If no geometries are in result collection, return NULL */
1419  if ( GEOSGetNumGeometries(geos_out) == 0 )
1420  {
1421  GEOSGeom_destroy(geos_out);
1422  return NULL;
1423  }
1424 
1425  geom_out = GEOS2LWGEOM(geos_out, is3d);
1426  GEOSGeom_destroy(geos_out);
1427 
1428 #if PARANOIA_LEVEL > 0
1429  if ( geom_out == NULL )
1430  {
1431  lwerror("serialization error");
1432  return NULL;
1433  }
1434 
1435 #endif
1436 
1437  return geom_out;
1438 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:89
uint8_t flags
Definition: liblwgeom.h:396
char lwgeom_geos_errmsg[LWGEOM_GEOS_ERRMSG_MAXSIZE]
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
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)
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:139
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, char want3d)
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1310
#define LWDEBUGF(level, msg,...)
Definition: lwgeom_log.h:88
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:102
GEOSGeometry * LWGEOM_GEOS_buildArea(const GEOSGeometry *geom_in)
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