PostGIS  3.1.6dev-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 651 of file measures.c.

652 {
653  const POINT2D *p = getPoint2d_cp(point->point, 0);
654 
655  /* Max distance? Check only outer ring.*/
656  if (dl->mode == DIST_MAX)
657  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
658 
659  /* Return distance to outer ring if not inside it */
660  if (ptarray_contains_point(poly->rings[0], p) == LW_OUTSIDE)
661  return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
662 
663  /*
664  * Inside the outer ring.
665  * Scan though each of the inner rings looking to
666  * see if its inside. If not, distance==0.
667  * Otherwise, distance = pt to ring distance
668  */
669  for (uint32_t i = 1; i < poly->nrings; i++)
670  if (ptarray_contains_point(poly->rings[i], p) != LW_OUTSIDE)
671  return lw_dist2d_pt_ptarray(p, poly->rings[i], dl);
672 
673  /* Is inside the polygon */
674  lw_dist2d_distpts_set(dl, 0.0, p, p);
675  return LW_TRUE;
676 }
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:107
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:740
#define LW_OUTSIDE
static const POINT2D * getPoint2d_cp(const POINTARRAY *pa, uint32_t n)
Returns a POINT2D pointer into the POINTARRAY serialized_ptlist, suitable for reading from.
Definition: lwinline.h:101
static void lw_dist2d_distpts_set(DISTPTS *dl, double distance, const POINT2D *p1, const POINT2D *p2)
Definition: measures.c:78
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:1107
#define DIST_MAX
Definition: measures.h:43
int mode
Definition: measures.h:54
POINTARRAY * point
Definition: liblwgeom.h:485
POINTARRAY ** rings
Definition: liblwgeom.h:533
uint32_t nrings
Definition: liblwgeom.h:538

References DIST_MAX, getPoint2d_cp(), lw_dist2d_distpts_set(), lw_dist2d_pt_ptarray(), LW_OUTSIDE, LW_TRUE, DISTPTS::mode, LWPOLY::nrings, LWPOINT::point, ptarray_contains_point(), and LWPOLY::rings.

Referenced by lw_dist2d_distribute_bruteforce().

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