PostGIS  3.0.6dev-r@@SVN_REVISION@@

◆ lw_dist2d_distancepoint()

LWGEOM* lw_dist2d_distancepoint ( const LWGEOM lw1,
const LWGEOM lw2,
int32_t  srid,
int  mode 
)

Function initializing closestpoint calculations.

Definition at line 128 of file measures.c.

129 {
130  double x, y;
131  DISTPTS thedl;
132  double initdistance = FLT_MAX;
133  LWGEOM *result;
134 
135  thedl.mode = mode;
136  thedl.distance = initdistance;
137  thedl.tolerance = 0;
138 
139  LWDEBUG(2, "lw_dist2d_distancepoint is called");
140 
141  if (!lw_dist2d_comp(lw1, lw2, &thedl))
142  {
143  /*should never get here. all cases ought to be error handled earlier*/
144  lwerror("Some unspecified error.");
145  result = (LWGEOM *)lwcollection_construct_empty(COLLECTIONTYPE, srid, 0, 0);
146  }
147  if (thedl.distance == initdistance)
148  {
149  LWDEBUG(3, "didn't find geometries to measure between, returning null");
150  result = (LWGEOM *)lwcollection_construct_empty(COLLECTIONTYPE, srid, 0, 0);
151  }
152  else
153  {
154  x = thedl.p1.x;
155  y = thedl.p1.y;
156  result = (LWGEOM *)lwpoint_make2d(srid, x, y);
157  }
158  return result;
159 }
#define COLLECTIONTYPE
Definition: liblwgeom.h:122
LWPOINT * lwpoint_make2d(int32_t srid, double x, double y)
Definition: lwpoint.c:163
LWCOLLECTION * lwcollection_construct_empty(uint8_t type, int32_t srid, char hasz, char hasm)
Definition: lwcollection.c:92
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
int lw_dist2d_comp(const LWGEOM *lw1, const LWGEOM *lw2, DISTPTS *dl)
This function just deserializes geometries Bboxes is not checked here since it is the subgeometries b...
Definition: measures.c:236
POINT2D p1
Definition: measures.h:52
double tolerance
Definition: measures.h:56
int mode
Definition: measures.h:54
double distance
Definition: measures.h:51
Structure used in distance-calculations.
Definition: measures.h:50
double y
Definition: liblwgeom.h:376
double x
Definition: liblwgeom.h:376

References COLLECTIONTYPE, DISTPTS::distance, lw_dist2d_comp(), lwcollection_construct_empty(), LWDEBUG, lwerror(), lwpoint_make2d(), DISTPTS::mode, DISTPTS::p1, DISTPTS::tolerance, POINT2D::x, pixval::x, POINT2D::y, and pixval::y.

Referenced by lw_dist3d_distancepoint(), lwgeom_closest_point(), and lwgeom_furthest_point().

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