PostGIS  2.5.0beta2dev-r@@SVN_REVISION@@

◆ lwgeom_segmentize_sphere()

LWGEOM* lwgeom_segmentize_sphere ( const LWGEOM lwg_in,
double  max_seg_length 
)

Create a new, densified geometry where no segment is longer than max_seg_length.

Derive a new geometry with vertices added to ensure no vertex is more than max_seg_length (in radians) from any other vertex.

Input geometry is not altered, output geometry must be freed by caller.

Parameters
lwg_in= input geometry
max_seg_length= maximum segment length in radians

Definition at line 1656 of file lwgeodetic.c.

References COLLECTIONTYPE, LWCOLLECTION::geoms, LINETYPE, lwcollection_add_lwgeom(), lwcollection_as_lwgeom(), lwcollection_construct_empty(), lwerror(), lwgeom_as_lwcollection(), lwgeom_as_lwline(), lwgeom_as_lwpoly(), lwgeom_clone(), lwgeom_clone_deep(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_is_empty(), lwline_as_lwgeom(), lwline_construct(), lwpoly_add_ring(), lwpoly_as_lwgeom(), lwpoly_construct_empty(), lwtype_name(), MULTILINETYPE, MULTIPOINTTYPE, MULTIPOLYGONTYPE, LWCOLLECTION::ngeoms, LWPOLY::nrings, LWLINE::points, POINTTYPE, POLYGONTYPE, ptarray_segmentize_sphere(), LWPOLY::rings, LWGEOM::srid, and LWGEOM::type.

Referenced by geography_segmentize(), test_geos_subdivide(), and test_lwgeom_segmentize_sphere().

1657 {
1658  POINTARRAY *pa_out;
1659  LWLINE *lwline;
1660  LWPOLY *lwpoly_in, *lwpoly_out;
1661  LWCOLLECTION *lwcol_in, *lwcol_out;
1662  uint32_t i;
1663 
1664  /* Reflect NULL */
1665  if ( ! lwg_in )
1666  return NULL;
1667 
1668  /* Clone empty */
1669  if ( lwgeom_is_empty(lwg_in) )
1670  return lwgeom_clone(lwg_in);
1671 
1672  switch (lwg_in->type)
1673  {
1674  case MULTIPOINTTYPE:
1675  case POINTTYPE:
1676  return lwgeom_clone_deep(lwg_in);
1677  break;
1678  case LINETYPE:
1679  lwline = lwgeom_as_lwline(lwg_in);
1680  pa_out = ptarray_segmentize_sphere(lwline->points, max_seg_length);
1681  return lwline_as_lwgeom(lwline_construct(lwg_in->srid, NULL, pa_out));
1682  break;
1683  case POLYGONTYPE:
1684  lwpoly_in = lwgeom_as_lwpoly(lwg_in);
1685  lwpoly_out = lwpoly_construct_empty(lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1686  for ( i = 0; i < lwpoly_in->nrings; i++ )
1687  {
1688  pa_out = ptarray_segmentize_sphere(lwpoly_in->rings[i], max_seg_length);
1689  lwpoly_add_ring(lwpoly_out, pa_out);
1690  }
1691  return lwpoly_as_lwgeom(lwpoly_out);
1692  break;
1693  case MULTILINETYPE:
1694  case MULTIPOLYGONTYPE:
1695  case COLLECTIONTYPE:
1696  lwcol_in = lwgeom_as_lwcollection(lwg_in);
1697  lwcol_out = lwcollection_construct_empty(lwg_in->type, lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1698  for ( i = 0; i < lwcol_in->ngeoms; i++ )
1699  {
1700  lwcollection_add_lwgeom(lwcol_out, lwgeom_segmentize_sphere(lwcol_in->geoms[i], max_seg_length));
1701  }
1702  return lwcollection_as_lwgeom(lwcol_out);
1703  break;
1704  default:
1705  lwerror("lwgeom_segmentize_sphere: unsupported input geometry type: %d - %s",
1706  lwg_in->type, lwtype_name(lwg_in->type));
1707  break;
1708  }
1709 
1710  lwerror("lwgeom_segmentize_sphere got to the end of the function, should not happen");
1711  return NULL;
1712 }
#define LINETYPE
Definition: liblwgeom.h:85
#define POLYGONTYPE
Definition: liblwgeom.h:86
#define MULTIPOINTTYPE
Definition: liblwgeom.h:87
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:520
LWPOLY * lwgeom_as_lwpoly(const LWGEOM *lwgeom)
Definition: lwgeom.c:206
uint32_t ngeoms
Definition: liblwgeom.h:509
int lwgeom_has_z(const LWGEOM *geom)
Return LW_TRUE if geometry has Z ordinates.
Definition: lwgeom.c:930
int32_t srid
Definition: liblwgeom.h:401
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:320
uint32_t nrings
Definition: liblwgeom.h:457
unsigned int uint32_t
Definition: uthash.h:78
const char * lwtype_name(uint8_t type)
Return the type name string associated with a type number (e.g.
Definition: lwutil.c:218
LWGEOM * lwline_as_lwgeom(const LWLINE *obj)
Definition: lwgeom.c:330
LWLINE * lwline_construct(int srid, GBOX *bbox, POINTARRAY *points)
Definition: lwline.c:42
LWGEOM ** geoms
Definition: liblwgeom.h:511
POINTARRAY ** rings
Definition: liblwgeom.h:459
static POINTARRAY * ptarray_segmentize_sphere(const POINTARRAY *pa_in, double max_seg_length)
Create a new point array with no segment longer than the input segment length (expressed in radians!)...
Definition: lwgeodetic.c:1597
LWGEOM * lwgeom_clone(const LWGEOM *lwgeom)
Clone LWGEOM object.
Definition: lwgeom.c:482
LWLINE * lwgeom_as_lwline(const LWGEOM *lwgeom)
Definition: lwgeom.c:170
#define MULTIPOLYGONTYPE
Definition: liblwgeom.h:89
LWGEOM * lwgeom_segmentize_sphere(const LWGEOM *lwg_in, double max_seg_length)
Create a new, densified geometry where no segment is longer than max_seg_length.
Definition: lwgeodetic.c:1656
LWCOLLECTION * lwgeom_as_lwcollection(const LWGEOM *lwgeom)
Definition: lwgeom.c:224
#define POINTTYPE
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:84
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:161
uint8_t type
Definition: liblwgeom.h:398
int lwpoly_add_ring(LWPOLY *poly, POINTARRAY *pa)
Add a ring, allocating extra space if necessary.
Definition: lwpoly.c:247
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:1393
#define MULTILINETYPE
Definition: liblwgeom.h:88
LWCOLLECTION * lwcollection_construct_empty(uint8_t type, int srid, char hasz, char hasm)
Definition: lwcollection.c:94
int lwgeom_has_m(const LWGEOM *geom)
Return LW_TRUE if geometry has M ordinates.
Definition: lwgeom.c:937
LWCOLLECTION * lwcollection_add_lwgeom(LWCOLLECTION *col, const LWGEOM *geom)
Appends geom to the collection managed by col.
Definition: lwcollection.c:187
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
#define COLLECTIONTYPE
Definition: liblwgeom.h:90
POINTARRAY * points
Definition: liblwgeom.h:424
LWGEOM * lwcollection_as_lwgeom(const LWCOLLECTION *obj)
Definition: lwgeom.c:300
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