PostGIS  2.3.8dev-r@@SVN_REVISION@@

◆ geography_dwithin()

Datum geography_dwithin ( PG_FUNCTION_ARGS  )

Definition at line 276 of file geography_measurement.c.

References SPHEROID::a, SPHEROID::b, distance(), error_if_srid_mismatch(), FALSE, geography_distance_tree(), geography_dwithin_cache(), gserialized_get_srid(), gserialized_is_empty(), LW_FAILURE, LW_FALSE, lwgeom_distance_spheroid(), lwgeom_free(), lwgeom_from_gserialized(), PG_FUNCTION_INFO_V1(), SPHEROID::radius, and s.

Referenced by geography_distance().

277 {
278  GSERIALIZED *g1 = NULL;
279  GSERIALIZED *g2 = NULL;
280  double tolerance = 0.0;
281  double distance;
282  bool use_spheroid = true;
283  SPHEROID s;
284  int dwithin = LW_FALSE;
285 
286  /* Get our geometry objects loaded into memory. */
287  g1 = PG_GETARG_GSERIALIZED_P(0);
288  g2 = PG_GETARG_GSERIALIZED_P(1);
289 
290  /* Read our tolerance value. */
291  if ( PG_NARGS() > 2 && ! PG_ARGISNULL(2) )
292  tolerance = PG_GETARG_FLOAT8(2);
293 
294  /* Read our calculation type. */
295  if ( PG_NARGS() > 3 && ! PG_ARGISNULL(3) )
296  use_spheroid = PG_GETARG_BOOL(3);
297 
299 
300  /* Initialize spheroid */
301  spheroid_init_from_srid(fcinfo, gserialized_get_srid(g1), &s);
302 
303  /* Set to sphere if requested */
304  if ( ! use_spheroid )
305  s.a = s.b = s.radius;
306 
307  /* Return FALSE on empty arguments. */
309  {
310  PG_FREE_IF_COPY(g1, 0);
311  PG_FREE_IF_COPY(g2, 1);
312  PG_RETURN_BOOL(FALSE);
313  }
314 
315  /* Do the brute force calculation if the cached calculation doesn't tick over */
316  if ( LW_FAILURE == geography_dwithin_cache(fcinfo, g1, g2, &s, tolerance, &dwithin) )
317  {
318  LWGEOM* lwgeom1 = lwgeom_from_gserialized(g1);
319  LWGEOM* lwgeom2 = lwgeom_from_gserialized(g2);
320  distance = lwgeom_distance_spheroid(lwgeom1, lwgeom2, &s, tolerance);
321  /* Something went wrong... */
322  if ( distance < 0.0 )
323  elog(ERROR, "lwgeom_distance_spheroid returned negative!");
324  dwithin = (distance <= tolerance);
325  lwgeom_free(lwgeom1);
326  lwgeom_free(lwgeom2);
327  }
328 
329  /* Clean up */
330  PG_FREE_IF_COPY(g1, 0);
331  PG_FREE_IF_COPY(g2, 1);
332 
333  PG_RETURN_BOOL(dwithin);
334 }
LWGEOM * lwgeom_from_gserialized(const GSERIALIZED *g)
Allocate a new LWGEOM from a GSERIALIZED.
double b
Definition: liblwgeom.h:313
void lwgeom_free(LWGEOM *geom)
Definition: lwgeom.c:1063
double radius
Definition: liblwgeom.h:317
void error_if_srid_mismatch(int srid1, int srid2)
Definition: lwutil.c:369
int gserialized_is_empty(const GSERIALIZED *g)
Check if a GSERIALIZED is empty without deserializing first.
Definition: g_serialized.c:153
#define LW_FAILURE
Definition: liblwgeom.h:78
#define LW_FALSE
Definition: liblwgeom.h:76
char * s
Definition: cu_in_wkt.c:23
Datum distance(PG_FUNCTION_ARGS)
double a
Definition: liblwgeom.h:312
int geography_dwithin_cache(FunctionCallInfoData *fcinfo, const GSERIALIZED *g1, const GSERIALIZED *g2, const SPHEROID *s, double tolerance, int *dwithin)
#define FALSE
Definition: dbfopen.c:168
double lwgeom_distance_spheroid(const LWGEOM *lwgeom1, const LWGEOM *lwgeom2, const SPHEROID *spheroid, double tolerance)
Calculate the geodetic distance from lwgeom1 to lwgeom2 on the spheroid.
Definition: lwgeodetic.c:2092
int32_t gserialized_get_srid(const GSERIALIZED *s)
Extract the SRID from the serialized form (it is packed into three bytes so this is a handy function)...
Definition: g_serialized.c:83
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