PostGIS  2.5.0dev-r@@SVN_REVISION@@
LWT_ELEMID lwt_AddIsoEdge ( LWT_TOPOLOGY topo,
LWT_ELEMID  startNode,
LWT_ELEMID  endNode,
const LWLINE geom 
)

Add an isolated edge connecting two existing isolated nodes.

For ST_AddIsoEdge

Parameters
topothe topology to operate on
start_nodeidentifier of the starting node
end_nodeidentifier of the ending node
geomthe edge geometry
Returns
ID of the newly added edge, or -1 on error (liblwgeom error handler will be invoked with error message)

Definition at line 797 of file lwgeom_topo.c.

References _lwt_CheckEdgeCrossing(), _lwt_release_nodes(), LWT_TOPOLOGY_T::be_iface, LWT_ISO_NODE::containing_face, LWT_ISO_EDGE::edge_id, LWT_ISO_EDGE::end_node, LWT_ISO_EDGE::face_left, LWT_ISO_EDGE::face_right, LWT_ISO_NODE::geom, LWT_ISO_EDGE::geom, getPoint2d_p(), lwerror(), lwgeom_is_simple(), lwline_as_lwgeom(), lwt_be_getNextEdgeId(), lwt_be_getNodeById(), lwt_be_insertEdges(), lwt_be_lastErrorMessage(), lwt_be_updateNodesById(), LWT_COL_NODE_ALL, LWT_COL_NODE_CONTAINING_FACE, LWT_ISO_EDGE::next_left, LWT_ISO_EDGE::next_right, LWT_ISO_NODE::node_id, POINTARRAY::npoints, p2d_same(), LWPOINT::point, LWLINE::points, and LWT_ISO_EDGE::start_node.

799 {
800  int num_nodes;
801  int i;
802  LWT_ISO_EDGE newedge;
803  LWT_ISO_NODE *endpoints;
804  LWT_ELEMID containing_face = -1;
805  LWT_ELEMID node_ids[2];
806  LWT_ISO_NODE updated_nodes[2];
807  int skipISOChecks = 0;
808  POINT2D p1, p2;
809 
810  /* NOT IN THE SPECS:
811  * A closed edge is never isolated (as it forms a face)
812  */
813  if ( startNode == endNode )
814  {
815  lwerror("Closed edges would not be isolated, try lwt_AddEdgeNewFaces");
816  return -1;
817  }
818 
819  if ( ! skipISOChecks )
820  {
821  /* Acurve must be simple */
822  if ( ! lwgeom_is_simple(lwline_as_lwgeom(geom)) )
823  {
824  lwerror("SQL/MM Spatial exception - curve not simple");
825  return -1;
826  }
827  }
828 
829  /*
830  * Check for:
831  * existence of nodes
832  * nodes faces match
833  * Extract:
834  * nodes face id
835  * nodes geoms
836  */
837  num_nodes = 2;
838  node_ids[0] = startNode;
839  node_ids[1] = endNode;
840  endpoints = lwt_be_getNodeById( topo, node_ids, &num_nodes,
842  if ( num_nodes < 0 )
843  {
844  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
845  return -1;
846  }
847  else if ( num_nodes < 2 )
848  {
849  if ( num_nodes ) _lwt_release_nodes(endpoints, num_nodes);
850  lwerror("SQL/MM Spatial exception - non-existent node");
851  return -1;
852  }
853  for ( i=0; i<num_nodes; ++i )
854  {
855  const LWT_ISO_NODE *n = &(endpoints[i]);
856  if ( n->containing_face == -1 )
857  {
858  _lwt_release_nodes(endpoints, num_nodes);
859  lwerror("SQL/MM Spatial exception - not isolated node");
860  return -1;
861  }
862  if ( containing_face == -1 ) containing_face = n->containing_face;
863  else if ( containing_face != n->containing_face )
864  {
865  _lwt_release_nodes(endpoints, num_nodes);
866  lwerror("SQL/MM Spatial exception - nodes in different faces");
867  return -1;
868  }
869 
870  if ( ! skipISOChecks )
871  {
872  if ( n->node_id == startNode )
873  {
874  /* l) Check that start point of acurve match start node geoms. */
875  getPoint2d_p(geom->points, 0, &p1);
876  getPoint2d_p(n->geom->point, 0, &p2);
877  if ( ! p2d_same(&p1, &p2) )
878  {
879  _lwt_release_nodes(endpoints, num_nodes);
880  lwerror("SQL/MM Spatial exception - "
881  "start node not geometry start point.");
882  return -1;
883  }
884  }
885  else
886  {
887  /* m) Check that end point of acurve match end node geoms. */
888  getPoint2d_p(geom->points, geom->points->npoints-1, &p1);
889  getPoint2d_p(n->geom->point, 0, &p2);
890  if ( ! p2d_same(&p1, &p2) )
891  {
892  _lwt_release_nodes(endpoints, num_nodes);
893  lwerror("SQL/MM Spatial exception - "
894  "end node not geometry end point.");
895  return -1;
896  }
897  }
898  }
899  }
900 
901  if ( num_nodes ) _lwt_release_nodes(endpoints, num_nodes);
902 
903  if ( ! skipISOChecks )
904  {
905  if ( _lwt_CheckEdgeCrossing( topo, startNode, endNode, geom, 0 ) )
906  {
907  /* would have called lwerror already, leaking :( */
908  return -1;
909  }
910  }
911 
912  /*
913  * All checks passed, time to prepare the new edge
914  */
915 
916  newedge.edge_id = lwt_be_getNextEdgeId( topo );
917  if ( newedge.edge_id == -1 ) {
918  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
919  return -1;
920  }
921 
922  /* TODO: this should likely be an exception instead ! */
923  if ( containing_face == -1 ) containing_face = 0;
924 
925  newedge.start_node = startNode;
926  newedge.end_node = endNode;
927  newedge.face_left = newedge.face_right = containing_face;
928  newedge.next_left = -newedge.edge_id;
929  newedge.next_right = newedge.edge_id;
930  newedge.geom = (LWLINE *)geom; /* const cast.. */
931 
932  int ret = lwt_be_insertEdges(topo, &newedge, 1);
933  if ( ret == -1 ) {
934  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
935  return -1;
936  } else if ( ret == 0 ) {
937  lwerror("Insertion of split edge failed (no reason)");
938  return -1;
939  }
940 
941  /*
942  * Update Node containing_face values
943  *
944  * the nodes anode and anothernode are no more isolated
945  * because now there is an edge connecting them
946  */
947  updated_nodes[0].node_id = startNode;
948  updated_nodes[0].containing_face = -1;
949  updated_nodes[1].node_id = endNode;
950  updated_nodes[1].containing_face = -1;
951  ret = lwt_be_updateNodesById(topo, updated_nodes, 2,
953  if ( ret == -1 ) {
954  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
955  return -1;
956  }
957 
958  return newedge.edge_id;
959 }
static int _lwt_CheckEdgeCrossing(LWT_TOPOLOGY *topo, LWT_ELEMID start_node, LWT_ELEMID end_node, const LWLINE *geom, LWT_ELEMID myself)
Definition: lwgeom_topo.c:601
static void _lwt_release_nodes(LWT_ISO_NODE *nodes, int num_nodes)
Definition: lwgeom_topo.c:467
LWT_ELEMID face_left
#define LWT_COL_NODE_CONTAINING_FACE
LWT_ELEMID containing_face
LWPOINT * geom
LWLINE * geom
POINTARRAY * point
Definition: liblwgeom.h:410
LWT_ELEMID next_left
int p2d_same(const POINT2D *p1, const POINT2D *p2)
Definition: lwalgorithm.c:49
LWGEOM * lwline_as_lwgeom(const LWLINE *obj)
Definition: lwgeom.c:329
const LWT_BE_IFACE * be_iface
LWT_ELEMID face_right
LWT_ELEMID node_id
LWT_ELEMID edge_id
static int lwt_be_updateNodesById(LWT_TOPOLOGY *topo, const LWT_ISO_NODE *nodes, int numnodes, int upd_fields)
Definition: lwgeom_topo.c:314
LWT_ELEMID lwt_be_getNextEdgeId(LWT_TOPOLOGY *topo)
Definition: lwgeom_topo.c:219
int getPoint2d_p(const POINTARRAY *pa, uint32_t n, POINT2D *point)
Definition: lwgeom_api.c:338
int lwt_be_insertEdges(LWT_TOPOLOGY *topo, LWT_ISO_EDGE *edge, int numelems)
Definition: lwgeom_topo.c:268
#define LWT_COL_NODE_ALL
LWT_ELEMID start_node
int lwgeom_is_simple(const LWGEOM *lwgeom)
LWT_ELEMID next_right
LWT_INT64 LWT_ELEMID
Identifier of topology element.
LWT_ISO_NODE * lwt_be_getNodeById(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields)
Definition: lwgeom_topo.c:156
LWT_ELEMID end_node
const char * lwt_be_lastErrorMessage(const LWT_BE_IFACE *be)
Definition: lwgeom_topo.c:120
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
POINTARRAY * points
Definition: liblwgeom.h:421
uint32_t npoints
Definition: liblwgeom.h:370

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