PostGIS  2.2.7dev-r@@SVN_REVISION@@
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 1639 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(), and test_lwgeom_segmentize_sphere().

1640 {
1641  POINTARRAY *pa_out;
1642  LWLINE *lwline;
1643  LWPOLY *lwpoly_in, *lwpoly_out;
1644  LWCOLLECTION *lwcol_in, *lwcol_out;
1645  int i;
1646 
1647  /* Reflect NULL */
1648  if ( ! lwg_in )
1649  return NULL;
1650 
1651  /* Clone empty */
1652  if ( lwgeom_is_empty(lwg_in) )
1653  return lwgeom_clone(lwg_in);
1654 
1655  switch (lwg_in->type)
1656  {
1657  case MULTIPOINTTYPE:
1658  case POINTTYPE:
1659  return lwgeom_clone_deep(lwg_in);
1660  break;
1661  case LINETYPE:
1662  lwline = lwgeom_as_lwline(lwg_in);
1663  pa_out = ptarray_segmentize_sphere(lwline->points, max_seg_length);
1664  return lwline_as_lwgeom(lwline_construct(lwg_in->srid, NULL, pa_out));
1665  break;
1666  case POLYGONTYPE:
1667  lwpoly_in = lwgeom_as_lwpoly(lwg_in);
1668  lwpoly_out = lwpoly_construct_empty(lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1669  for ( i = 0; i < lwpoly_in->nrings; i++ )
1670  {
1671  pa_out = ptarray_segmentize_sphere(lwpoly_in->rings[i], max_seg_length);
1672  lwpoly_add_ring(lwpoly_out, pa_out);
1673  }
1674  return lwpoly_as_lwgeom(lwpoly_out);
1675  break;
1676  case MULTILINETYPE:
1677  case MULTIPOLYGONTYPE:
1678  case COLLECTIONTYPE:
1679  lwcol_in = lwgeom_as_lwcollection(lwg_in);
1680  lwcol_out = lwcollection_construct_empty(lwg_in->type, lwg_in->srid, lwgeom_has_z(lwg_in), lwgeom_has_m(lwg_in));
1681  for ( i = 0; i < lwcol_in->ngeoms; i++ )
1682  {
1683  lwcollection_add_lwgeom(lwcol_out, lwgeom_segmentize_sphere(lwcol_in->geoms[i], max_seg_length));
1684  }
1685  return lwcollection_as_lwgeom(lwcol_out);
1686  break;
1687  default:
1688  lwerror("lwgeom_segmentize_sphere: unsupported input geometry type: %d - %s",
1689  lwg_in->type, lwtype_name(lwg_in->type));
1690  break;
1691  }
1692 
1693  lwerror("lwgeom_segmentize_sphere got to the end of the function, should not happen");
1694  return NULL;
1695 }
#define LINETYPE
Definition: liblwgeom.h:71
#define POLYGONTYPE
Definition: liblwgeom.h:72
#define MULTIPOINTTYPE
Definition: liblwgeom.h:73
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:433
LWPOLY * lwgeom_as_lwpoly(const LWGEOM *lwgeom)
Definition: lwgeom.c:125
int lwgeom_has_z(const LWGEOM *geom)
Return LW_TRUE if geometry has Z ordinates.
Definition: lwgeom.c:836
int32_t srid
Definition: liblwgeom.h:383
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:239
const char * lwtype_name(uint8_t type)
Return the type name string associated with a type number (e.g.
Definition: lwutil.c:188
LWGEOM * lwline_as_lwgeom(const LWLINE *obj)
Definition: lwgeom.c:249
LWLINE * lwline_construct(int srid, GBOX *bbox, POINTARRAY *points)
Definition: lwline.c:29
LWGEOM ** geoms
Definition: liblwgeom.h:493
POINTARRAY ** rings
Definition: liblwgeom.h:441
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:1531
int nrings
Definition: liblwgeom.h:439
LWGEOM * lwgeom_clone(const LWGEOM *lwgeom)
Clone LWGEOM object.
Definition: lwgeom.c:395
LWLINE * lwgeom_as_lwline(const LWGEOM *lwgeom)
Definition: lwgeom.c:89
#define MULTIPOLYGONTYPE
Definition: liblwgeom.h:75
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:1639
LWCOLLECTION * lwgeom_as_lwcollection(const LWGEOM *lwgeom)
Definition: lwgeom.c:143
#define POINTTYPE
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:70
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:66
uint8_t type
Definition: liblwgeom.h:380
int lwpoly_add_ring(LWPOLY *poly, POINTARRAY *pa)
Add a ring, allocating extra space if necessary.
Definition: lwpoly.c:154
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 MULTILINETYPE
Definition: liblwgeom.h:74
LWCOLLECTION * lwcollection_construct_empty(uint8_t type, int srid, char hasz, char hasm)
Definition: lwcollection.c:81
int lwgeom_has_m(const LWGEOM *geom)
Return LW_TRUE if geometry has M ordinates.
Definition: lwgeom.c:843
LWCOLLECTION * lwcollection_add_lwgeom(LWCOLLECTION *col, const LWGEOM *geom)
Appends geom to the collection managed by col.
Definition: lwcollection.c:174
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:74
#define COLLECTIONTYPE
Definition: liblwgeom.h:76
POINTARRAY * points
Definition: liblwgeom.h:406
LWGEOM * lwcollection_as_lwgeom(const LWCOLLECTION *obj)
Definition: lwgeom.c:219

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