PostGIS 3.0.6dev-r@@SVN_REVISION@@
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◆ 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 641 of file measures.c.

642{
643 const POINT2D *p = getPoint2d_cp(point->point, 0);
644
645 /* Max distance? Check only outer ring.*/
646 if (dl->mode == DIST_MAX)
647 return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
648
649 /* Return distance to outer ring if not inside it */
650 if (ptarray_contains_point(poly->rings[0], p) == LW_OUTSIDE)
651 return lw_dist2d_pt_ptarray(p, poly->rings[0], dl);
652
653 /*
654 * Inside the outer ring.
655 * Scan though each of the inner rings looking to
656 * see if its inside. If not, distance==0.
657 * Otherwise, distance = pt to ring distance
658 */
659 for (uint32_t i = 1; i < poly->nrings; i++)
660 if (ptarray_contains_point(poly->rings[i], p) != LW_OUTSIDE)
661 return lw_dist2d_pt_ptarray(p, poly->rings[i], dl);
662
663 /* Is inside the polygon */
664 dl->distance = 0.0;
665 dl->p1.x = dl->p2.x = p->x;
666 dl->p1.y = dl->p2.y = p->y;
667 return LW_TRUE;
668}
#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:91
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:1129
#define DIST_MAX
Definition measures.h:43
POINT2D p1
Definition measures.h:52
POINT2D p2
Definition measures.h:53
int mode
Definition measures.h:54
double distance
Definition measures.h:51
POINTARRAY * point
Definition liblwgeom.h:457
POINTARRAY ** rings
Definition liblwgeom.h:505
uint32_t nrings
Definition liblwgeom.h:510
double y
Definition liblwgeom.h:376
double x
Definition liblwgeom.h:376

References DIST_MAX, DISTPTS::distance, getPoint2d_cp(), lw_dist2d_pt_ptarray(), LW_OUTSIDE, LW_TRUE, 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().

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