PostGIS  2.5.1dev-r@@SVN_REVISION@@

◆ lw_dist2d_point_poly()

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 615 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().

616 {
617  const POINT2D *p;
618  uint32_t i;
619 
620  LWDEBUG(2, "lw_dist2d_point_poly called");
621 
622  p = getPoint2d_cp(point->point, 0);
623 
624  if (dl->mode == DIST_MAX)
625  {
626  LWDEBUG(3, "looking for maxdistance");
627  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
628  }
629  /* Return distance to outer ring if not inside it */
630  if ( ptarray_contains_point(poly->rings[0], p) == LW_OUTSIDE )
631  {
632  LWDEBUG(3, "first point not inside outer-ring");
633  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
634  }
635 
636  /*
637  * Inside the outer ring.
638  * Scan though each of the inner rings looking to
639  * see if its inside. If not, distance==0.
640  * Otherwise, distance = pt to ring distance
641  */
642  for ( i = 1; i < poly->nrings; i++)
643  {
644  /* Inside a hole. Distance = pt -> ring */
645  if ( ptarray_contains_point(poly->rings[i], p) != LW_OUTSIDE )
646  {
647  LWDEBUG(3, " inside an hole");
648  return lw_dist2d_pt_ptarray(p, poly->rings[i], dl);
649  }
650  }
651 
652  LWDEBUG(3, " inside the polygon");
653  if (dl->mode == DIST_MIN)
654  {
655  dl->distance = 0.0;
656  dl->p1.x = dl->p2.x = p->x;
657  dl->p1.y = dl->p2.y = p->y;
658  }
659  return LW_TRUE; /* Is inside the polygon */
660 }
int mode
Definition: measures.h:51
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
POINTARRAY * point
Definition: liblwgeom.h:413
uint32_t nrings
Definition: liblwgeom.h:457
POINT2D p1
Definition: measures.h:49
unsigned int uint32_t
Definition: uthash.h:78
double x
Definition: liblwgeom.h:330
#define DIST_MIN
Definition: measures.h:41
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:75
POINTARRAY ** rings
Definition: liblwgeom.h:459
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:1053
POINT2D p2
Definition: measures.h:50
double y
Definition: liblwgeom.h:330
double distance
Definition: measures.h:48
#define DIST_MAX
Definition: measures.h:40
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:734
#define LW_OUTSIDE
const POINT2D * getPoint2d_cp(const POINTARRAY *pa, uint32_t n)
Returns a POINT2D pointer into the POINTARRAY serialized_ptlist, suitable for reading from...
Definition: lwgeom_api.c:364
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