PostGIS  2.5.0dev-r@@SVN_REVISION@@

◆ lwpoly_covers_lwpoly()

int lwpoly_covers_lwpoly ( const LWPOLY poly1,
const LWPOLY poly2 
)

Given a polygon1 check if all points of polygon2 are inside polygon1 and no intersections of the polygon edges occur.

return LW_TRUE if polygon is inside or on edge of polygon.

Definition at line 2515 of file lwgeodetic.c.

References LW_FALSE, LW_TRUE, LWDEBUG, lwgeom_is_empty(), lwpoly_covers_pointarray(), and lwpoly_intersects_line().

Referenced by lwgeom_covers_lwgeom_sphere().

2516 {
2517  uint32_t i;
2518 
2519  /* Nulls and empties don't contain anything! */
2520  if ( ! poly1 || lwgeom_is_empty((LWGEOM*)poly1) )
2521  {
2522  LWDEBUG(4,"returning false, geometry1 is empty or null");
2523  return LW_FALSE;
2524  }
2525 
2526  /* Nulls and empties don't contain anything! */
2527  if ( ! poly2 || lwgeom_is_empty((LWGEOM*)poly2) )
2528  {
2529  LWDEBUG(4,"returning false, geometry2 is empty or null");
2530  return LW_FALSE;
2531  }
2532 
2533  /* check if all vertices of poly2 are inside poly1 */
2534  for (i = 0; i < poly2->nrings; i++)
2535  {
2536 
2537  /* every other ring is a hole, check if point is inside the actual polygon */
2538  if ( i % 2 == 0)
2539  {
2540  if (LW_FALSE == lwpoly_covers_pointarray(poly1, poly2->rings[i]))
2541  {
2542  LWDEBUG(4,"returning false, geometry2 has point outside of geometry1");
2543  return LW_FALSE;
2544  }
2545  }
2546  else
2547  {
2548  if (LW_TRUE == lwpoly_covers_pointarray(poly1, poly2->rings[i]))
2549  {
2550  LWDEBUG(4,"returning false, geometry2 has point inside a hole of geometry1");
2551  return LW_FALSE;
2552  }
2553  }
2554  }
2555 
2556  /* check for any edge intersections, so nothing is partially outside of poly1 */
2557  for (i = 0; i < poly2->nrings; i++)
2558  {
2559  if (LW_TRUE == lwpoly_intersects_line(poly1, poly2->rings[i]))
2560  {
2561  LWDEBUG(4,"returning false, geometry2 is partially outside of geometry1");
2562  return LW_FALSE;
2563  }
2564  }
2565 
2566  /* no abort condition found, so the poly2 should be completly inside poly1 */
2567  return LW_TRUE;
2568 }
int lwpoly_intersects_line(const LWPOLY *lwpoly, const POINTARRAY *line)
Checks if any edges of lwpoly intersect with the line formed by the pointarray return LW_TRUE if any ...
Definition: lwgeodetic.c:2628
int lwpoly_covers_pointarray(const LWPOLY *lwpoly, const POINTARRAY *pta)
return LW_TRUE if all points are inside the polygon
Definition: lwgeodetic.c:2609
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
unsigned int uint32_t
Definition: uthash.h:78
#define LW_FALSE
Definition: liblwgeom.h:76
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:75
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1393
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