PostGIS  2.2.7dev-r@@SVN_REVISION@@
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 1302 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().

1303 {
1304  GEOSGeometry* geos_in;
1305  GEOSGeometry* geos_out;
1306  LWGEOM* geom_out;
1307  int SRID = (int)(geom->srid);
1308  int is3d = FLAGS_GET_Z(geom->flags);
1309 
1310  /* Can't build an area from an empty! */
1311  if ( lwgeom_is_empty(geom) )
1312  {
1313  return (LWGEOM*)lwpoly_construct_empty(SRID, is3d, 0);
1314  }
1315 
1316  LWDEBUG(3, "buildarea called");
1317 
1318  LWDEBUGF(3, "ST_BuildArea got geom @ %p", geom);
1319 
1320  initGEOS(lwnotice, lwgeom_geos_error);
1321 
1322  geos_in = LWGEOM2GEOS(geom, 0);
1323 
1324  if ( 0 == geos_in ) /* exception thrown at construction */
1325  {
1326  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
1327  return NULL;
1328  }
1329  geos_out = LWGEOM_GEOS_buildArea(geos_in);
1330  GEOSGeom_destroy(geos_in);
1331 
1332  if ( ! geos_out ) /* exception thrown.. */
1333  {
1334  lwerror("LWGEOM_GEOS_buildArea: %s", lwgeom_geos_errmsg);
1335  return NULL;
1336  }
1337 
1338  /* If no geometries are in result collection, return NULL */
1339  if ( GEOSGetNumGeometries(geos_out) == 0 )
1340  {
1341  GEOSGeom_destroy(geos_out);
1342  return NULL;
1343  }
1344 
1345  geom_out = GEOS2LWGEOM(geos_out, is3d);
1346  GEOSGeom_destroy(geos_out);
1347 
1348 #if PARANOIA_LEVEL > 0
1349  if ( geom_out == NULL )
1350  {
1351  lwerror("serialization error");
1352  return NULL;
1353  }
1354 
1355 #endif
1356 
1357  return geom_out;
1358 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:61
uint8_t flags
Definition: liblwgeom.h:381
char lwgeom_geos_errmsg[LWGEOM_GEOS_ERRMSG_MAXSIZE]
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:50
int32_t srid
Definition: liblwgeom.h:383
void lwgeom_geos_error(const char *fmt,...)
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:124
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, int autofix)
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:66
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:1297
#define LWDEBUGF(level, msg,...)
Definition: lwgeom_log.h:55
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:74
GEOSGeometry * LWGEOM_GEOS_buildArea(const GEOSGeometry *geom_in)

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