PostGIS  3.4.0dev-r@@SVN_REVISION@@

◆ geography_segmentize()

Datum geography_segmentize ( PG_FUNCTION_ARGS  )

Definition at line 1167 of file geography_measurement.c.

1168 {
1169  LWGEOM *lwgeom1 = NULL;
1170  LWGEOM *lwgeom2 = NULL;
1171  GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
1172  GSERIALIZED *g2 = NULL;
1173  double max_seg_length = PG_GETARG_FLOAT8(1) / WGS84_RADIUS;
1174  uint32_t type1 = gserialized_get_type(g1);
1175 
1176  /* We can't densify points or points, reflect them back */
1177  if ( type1 == POINTTYPE || type1 == MULTIPOINTTYPE || gserialized_is_empty(g1) )
1178  PG_RETURN_POINTER(g1);
1179 
1180  /* Deserialize */
1181  lwgeom1 = lwgeom_from_gserialized(g1);
1182 
1183  /* Calculate the densified geometry */
1184  lwgeom2 = lwgeom_segmentize_sphere(lwgeom1, max_seg_length);
1185 
1186  /*
1187  ** Set the geodetic flag so subsequent
1188  ** functions do the right thing.
1189  */
1190  lwgeom_set_geodetic(lwgeom2, true);
1191 
1192  /* Recalculate the boxes after re-setting the geodetic bit */
1193  lwgeom_drop_bbox(lwgeom2);
1194 
1195  /* We are trusting geography_serialize will add a box if needed */
1196  g2 = geography_serialize(lwgeom2);
1197 
1198  /* Clean up */
1199  lwgeom_free(lwgeom1);
1200  lwgeom_free(lwgeom2);
1201  PG_FREE_IF_COPY(g1, 0);
1202 
1203  PG_RETURN_POINTER(g2);
1204 }
LWGEOM * lwgeom_from_gserialized(const GSERIALIZED *g)
Allocate a new LWGEOM from a GSERIALIZED.
Definition: gserialized.c:239
int gserialized_is_empty(const GSERIALIZED *g)
Check if a GSERIALIZED is empty without deserializing first.
Definition: gserialized.c:152
uint32_t gserialized_get_type(const GSERIALIZED *g)
Extract the geometry type from the serialized form (it hides in the anonymous data area,...
Definition: gserialized.c:89
void lwgeom_set_geodetic(LWGEOM *geom, int value)
Set the FLAGS geodetic bit on geometry an all sub-geometries and pointlists.
Definition: lwgeom.c:964
LWGEOM * lwgeom_segmentize_sphere(const LWGEOM *lwg_in, double max_seg_length)
Derive a new geometry with vertices added to ensure no vertex is more than max_seg_length (in radians...
Definition: lwgeodetic.c:1749
void lwgeom_free(LWGEOM *geom)
Definition: lwgeom.c:1155
#define WGS84_RADIUS
Definition: liblwgeom.h:148
#define MULTIPOINTTYPE
Definition: liblwgeom.h:105
#define POINTTYPE
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:102
void lwgeom_drop_bbox(LWGEOM *lwgeom)
Call this function to drop BBOX and SRID from LWGEOM.
Definition: lwgeom.c:682

References gserialized_get_type(), gserialized_is_empty(), lwgeom_drop_bbox(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_segmentize_sphere(), lwgeom_set_geodetic(), MULTIPOINTTYPE, POINTTYPE, and WGS84_RADIUS.

Here is the call graph for this function: