PostGIS  2.2.8dev-r@@SVN_REVISION@@

◆ lw_dist3d_point_poly()

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 598 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().

599 {
600  POINT3DZ p, projp;/*projp is "point projected on plane"*/
601  PLANE3D plane;
602  LWDEBUG(2, "lw_dist3d_point_poly is called");
603  getPoint3dz_p(point->point, 0, &p);
604 
605  /*If we are lookig for max distance, longestline or dfullywithin*/
606  if (dl->mode == DIST_MAX)
607  {
608  LWDEBUG(3, "looking for maxdistance");
609  return lw_dist3d_pt_ptarray(&p, poly->rings[0], dl);
610  }
611 
612  /*Find the plane of the polygon, the "holes" have to be on the same plane. so we only care about the boudary*/
613  if(!define_plane(poly->rings[0], &plane))
614  return LW_FALSE;
615 
616  /*get our point projected on the plane of the polygon*/
617  project_point_on_plane(&p, &plane, &projp);
618 
619  return lw_dist3d_pt_poly(&p, poly,&plane, &projp, dl);
620 }
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:50
POINTARRAY * point
Definition: liblwgeom.h:395
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:1179
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:996
int getPoint3dz_p(const POINTARRAY *pa, int n, POINT3DZ *point)
Definition: lwgeom_api.c:319
#define LW_FALSE
Definition: liblwgeom.h:62
POINTARRAY ** rings
Definition: liblwgeom.h:441
int mode
Definition: measures3d.h:30
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:1113
#define DIST_MAX
Definition: measures.h:16
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:693
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