PostGIS  2.3.7dev-r@@SVN_REVISION@@
int lw_dist3d_point_poly ( LWPOINT point,
LWPOLY poly,
DISTPTS3D dl 
)

Computes point to polygon distance For mindistance that means: 1)find the plane of the polygon 2)projecting the point to the plane of the polygon 3)finding if that projected point is inside the polygon, if so the distance is measured to that projected point 4) if not in polygon above, check the distance against the boundary of the polygon for max distance it is always point against boundary.

Definition at line 622 of file measures3d.c.

References define_plane(), DIST_MAX, getPoint3dz_p(), lw_dist3d_pt_poly(), lw_dist3d_pt_ptarray(), LW_FALSE, LWDEBUG, DISTPTS3D::mode, LWPOINT::point, project_point_on_plane(), and LWPOLY::rings.

Referenced by lw_dist3d_distribute_bruteforce().

623 {
624  POINT3DZ p, projp;/*projp is "point projected on plane"*/
625  PLANE3D plane;
626  LWDEBUG(2, "lw_dist3d_point_poly is called");
627  getPoint3dz_p(point->point, 0, &p);
628 
629  /*If we are lookig for max distance, longestline or dfullywithin*/
630  if (dl->mode == DIST_MAX)
631  {
632  LWDEBUG(3, "looking for maxdistance");
633  return lw_dist3d_pt_ptarray(&p, poly->rings[0], dl);
634  }
635 
636  /*Find the plane of the polygon, the "holes" have to be on the same plane. so we only care about the boudary*/
637  if(!define_plane(poly->rings[0], &plane))
638  return LW_FALSE;
639 
640  /*get our point projected on the plane of the polygon*/
641  project_point_on_plane(&p, &plane, &projp);
642 
643  return lw_dist3d_pt_poly(&p, poly,&plane, &projp, dl);
644 }
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
POINTARRAY * point
Definition: liblwgeom.h:410
double project_point_on_plane(POINT3DZ *p, PLANE3D *pl, POINT3DZ *p0)
Finds a point on a plane from where the original point is perpendicular to the plane.
Definition: measures3d.c:1203
int lw_dist3d_pt_poly(POINT3DZ *p, LWPOLY *poly, PLANE3D *plane, POINT3DZ *projp, DISTPTS3D *dl)
Checking if the point projected on the plane of the polygon actually is inside that polygon...
Definition: measures3d.c:1020
int getPoint3dz_p(const POINTARRAY *pa, int n, POINT3DZ *point)
Definition: lwgeom_api.c:332
#define LW_FALSE
Definition: liblwgeom.h:76
POINTARRAY ** rings
Definition: liblwgeom.h:456
int mode
Definition: measures3d.h:44
int define_plane(POINTARRAY *pa, PLANE3D *pl)
Here we define the plane of a polygon (boundary pointarray of a polygon) the plane is stored as a pon...
Definition: measures3d.c:1137
#define DIST_MAX
Definition: measures.h:40
int lw_dist3d_pt_ptarray(POINT3DZ *p, POINTARRAY *pa, DISTPTS3D *dl)
search all the segments of pointarray to see which one is closest to p Returns distance between point...
Definition: measures3d.c:717

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