PostGIS  2.5.7dev-r@@SVN_REVISION@@

◆ lwgeom_segmentize_sphere()

LWGEOM* lwgeom_segmentize_sphere ( const LWGEOM lwg_in,
double  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.

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.

lwg_in= input geometry
max_seg_length= maximum segment length in radians

Definition at line 1743 of file lwgeodetic.c.

1744 {
1745  POINTARRAY *pa_out;
1746  LWLINE *lwline;
1747  LWPOLY *lwpoly_in, *lwpoly_out;
1748  LWCOLLECTION *lwcol_in, *lwcol_out;
1749  uint32_t i;
1751  /* Reflect NULL */
1752  if ( ! lwg_in )
1753  return NULL;
1755  /* Clone empty */
1756  if ( lwgeom_is_empty(lwg_in) )
1757  return lwgeom_clone(lwg_in);
1759  switch (lwg_in->type)
1760  {
1762  case POINTTYPE:
1763  return lwgeom_clone_deep(lwg_in);
1764  break;
1765  case LINETYPE:
1766  lwline = lwgeom_as_lwline(lwg_in);
1767  pa_out = ptarray_segmentize_sphere(lwline->points, max_seg_length);
1768  return lwline_as_lwgeom(lwline_construct(lwg_in->srid, NULL, pa_out));
1769  break;
1770  case POLYGONTYPE:
1771  lwpoly_in = lwgeom_as_lwpoly(lwg_in);
1772  lwpoly_out = lwpoly_construct_empty(lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1773  for ( i = 0; i < lwpoly_in->nrings; i++ )
1774  {
1775  pa_out = ptarray_segmentize_sphere(lwpoly_in->rings[i], max_seg_length);
1776  lwpoly_add_ring(lwpoly_out, pa_out);
1777  }
1778  return lwpoly_as_lwgeom(lwpoly_out);
1779  break;
1783  lwcol_in = lwgeom_as_lwcollection(lwg_in);
1784  lwcol_out = lwcollection_construct_empty(lwg_in->type, lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1785  for ( i = 0; i < lwcol_in->ngeoms; i++ )
1786  {
1787  lwcollection_add_lwgeom(lwcol_out, lwgeom_segmentize_sphere(lwcol_in->geoms[i], max_seg_length));
1788  }
1789  return lwcollection_as_lwgeom(lwcol_out);
1790  break;
1791  default:
1792  lwerror("lwgeom_segmentize_sphere: unsupported input geometry type: %d - %s",
1793  lwg_in->type, lwtype_name(lwg_in->type));
1794  break;
1795  }
1797  lwerror("lwgeom_segmentize_sphere got to the end of the function, should not happen");
1798  return NULL;
1799 }
LWLINE * lwgeom_as_lwline(const LWGEOM *lwgeom)
Definition: lwgeom.c:170
LWGEOM * lwline_as_lwgeom(const LWLINE *obj)
Definition: lwgeom.c:330
LWGEOM * lwcollection_as_lwgeom(const LWCOLLECTION *obj)
Definition: lwgeom.c:300
Definition: liblwgeom.h:91
LWCOLLECTION * lwcollection_construct_empty(uint8_t type, int srid, char hasz, char hasm)
Definition: lwcollection.c:94
Definition: liblwgeom.h:89
#define LINETYPE
Definition: liblwgeom.h:86
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:320
Definition: liblwgeom.h:88
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:520
int lwpoly_add_ring(LWPOLY *poly, POINTARRAY *pa)
Add a ring, allocating extra space if necessary.
Definition: lwpoly.c:247
int lwgeom_has_z(const LWGEOM *geom)
Return LW_TRUE if geometry has Z ordinates.
Definition: lwgeom.c:930
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:85
Definition: liblwgeom.h:90
Definition: liblwgeom.h:87
const char * lwtype_name(uint8_t type)
Return the type name string associated with a type number (e.g.
Definition: lwutil.c:218
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
LWGEOM * lwgeom_clone(const LWGEOM *lwgeom)
Clone LWGEOM object.
Definition: lwgeom.c:482
LWCOLLECTION * lwcollection_add_lwgeom(LWCOLLECTION *col, const LWGEOM *geom)
Appends geom to the collection managed by col.
Definition: lwcollection.c:187
LWCOLLECTION * lwgeom_as_lwcollection(const LWGEOM *lwgeom)
Definition: lwgeom.c:224
LWPOLY * lwgeom_as_lwpoly(const LWGEOM *lwgeom)
Definition: lwgeom.c:206
int lwgeom_has_m(const LWGEOM *geom)
Return LW_TRUE if geometry has M ordinates.
Definition: lwgeom.c:937
LWLINE * lwline_construct(int srid, GBOX *bbox, POINTARRAY *points)
Definition: lwline.c:42
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:161
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:1743
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:1684
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
uint32_t ngeoms
Definition: liblwgeom.h:510
LWGEOM ** geoms
Definition: liblwgeom.h:512
uint8_t type
Definition: liblwgeom.h:399
int32_t srid
Definition: liblwgeom.h:402
Definition: liblwgeom.h:425
Definition: liblwgeom.h:460
uint32_t nrings
Definition: liblwgeom.h:458
unsigned int uint32_t
Definition: uthash.h:78

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(), lwgeom_segmentize_sphere(), 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(), lwgeom_segmentize_sphere(), test_geos_subdivide(), and test_lwgeom_segmentize_sphere().

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