PostGIS  2.1.10dev-r@@SVN_REVISION@@
int lw_dist2d_point_poly ( LWPOINT point,
LWPOLY poly,
DISTPTS dl 
)
  1. see if pt in outer boundary. if no, then treat the outer ring like a line
  2. if in the boundary, test to see if its in a hole. if so, then return dist to hole, else return 0 (point in polygon)

Definition at line 571 of file measures.c.

References DIST_MAX, DIST_MIN, DISTPTS::distance, getPoint2d_cp(), lw_dist2d_pt_ptarray(), LW_OUTSIDE, LW_TRUE, LWDEBUG, DISTPTS::mode, LWPOLY::nrings, DISTPTS::p1, DISTPTS::p2, LWPOINT::point, ptarray_contains_point(), LWPOLY::rings, POINT2D::x, and POINT2D::y.

Referenced by lw_dist2d_distribute_bruteforce().

572 {
573  const POINT2D *p;
574  int i;
575 
576  LWDEBUG(2, "lw_dist2d_point_poly called");
577 
578  p = getPoint2d_cp(point->point, 0);
579 
580  if (dl->mode == DIST_MAX)
581  {
582  LWDEBUG(3, "looking for maxdistance");
583  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
584  }
585  /* Return distance to outer ring if not inside it */
586  if ( ptarray_contains_point(poly->rings[0], p) == LW_OUTSIDE )
587  {
588  LWDEBUG(3, "first point not inside outer-ring");
589  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
590  }
591 
592  /*
593  * Inside the outer ring.
594  * Scan though each of the inner rings looking to
595  * see if its inside. If not, distance==0.
596  * Otherwise, distance = pt to ring distance
597  */
598  for ( i = 1; i < poly->nrings; i++)
599  {
600  /* Inside a hole. Distance = pt -> ring */
601  if ( ptarray_contains_point(poly->rings[i], p) != LW_OUTSIDE )
602  {
603  LWDEBUG(3, " inside an hole");
604  return lw_dist2d_pt_ptarray(p, poly->rings[i], dl);
605  }
606  }
607 
608  LWDEBUG(3, " inside the polygon");
609  if (dl->mode == DIST_MIN)
610  {
611  dl->distance = 0.0;
612  dl->p1.x = dl->p2.x = p->x;
613  dl->p1.y = dl->p2.y = p->y;
614  }
615  return LW_TRUE; /* Is inside the polygon */
616 }
#define DIST_MAX
int mode
Definition: measures.h:26
#define DIST_MIN
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:50
POINTARRAY * point
Definition: liblwgeom.h:367
POINT2D p1
Definition: measures.h:24
double x
Definition: liblwgeom.h:284
const POINT2D * getPoint2d_cp(const POINTARRAY *pa, int n)
Returns a POINT2D pointer into the POINTARRAY serialized_ptlist, suitable for reading from...
Definition: lwgeom_api.c:458
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:51
POINTARRAY ** rings
Definition: liblwgeom.h:413
int lw_dist2d_pt_ptarray(const POINT2D *p, POINTARRAY *pa, DISTPTS *dl)
search all the segments of pointarray to see which one is closest to p1 Returns minimum distance betw...
Definition: measures.c:1009
POINT2D p2
Definition: measures.h:25
int nrings
Definition: liblwgeom.h:411
double y
Definition: liblwgeom.h:284
double distance
Definition: measures.h:23
int ptarray_contains_point(const POINTARRAY *pa, const POINT2D *pt)
Return 1 if the point is inside the POINTARRAY, -1 if it is outside, and 0 if it is on the boundary...
Definition: ptarray.c:697
#define LW_OUTSIDE

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