_lwt_SnapEdge_checkMotion()

static int _lwt_SnapEdge_checkMotion ( LWT_TOPOLOGY *  topo, const LWCOLLECTION *  splitC, const LWT_ISO_EDGE *  edge, LWT_ISO_EDGE *  existingEdge, const LWT_NODE_EDGES *  splitNodeEdges  )

static

Check the motion of a snapped edge, invoke lwerror if the movement hits any other edge or node.

Parameters

topo	the Topology we are working on
splitC	the result of the edge being split
edge	the edge before the split/snap
existingEdge	an edge on which one component of the split edge collapsed, or null if no collapse happened.
splitNodeEdges	all edges attached to the split node

TODO: check that newSplitEdgeLine retains its position in the edge end star (see ticket #5786) TODO: check that the motion range does not contain any node

Definition at line 5205 of file lwgeom_topo.c.

{
  // build the motion range shape: splitC->geoms[0] + splitC->geoms[1] - edge->geom
  POINTARRAY *motionRange = ptarray_clone_deep(lwgeom_as_lwline(splitC->geoms[0])->points);
  ptarray_append_ptarray(motionRange, lwgeom_as_lwline(splitC->geoms[1])->points, 0);
  POINTARRAY *reverseNewLine = ptarray_clone_deep(edge->geom->points);
  ptarray_reverse_in_place(reverseNewLine);
  ptarray_append_ptarray(motionRange, reverseNewLine, 0);
  ptarray_free(reverseNewLine);
 
  // motionBounds takes ownership of motionRange
  LWLINE *motionBounds = lwline_construct(topo->srid, NULL, motionRange);
 
  // motionPolyBare takes ownership of motionBounds
  LWGEOM *motionPolyBare = (LWGEOM *)lwpoly_from_lwlines(motionBounds, 0, NULL);
  LWGEOM *motionPoly = lwgeom_make_valid(motionPolyBare);
  lwgeom_free(motionPolyBare);
 
  LWDEBUGG(1, motionPoly, "Motion range");
 
  // check the Motion range doesn't cover any of
  // the edges incident to the split node other
  // than the existing edge
  GEOSGeometry *motionPolyG = NULL;
  for ( uint64_t t=0; t<splitNodeEdges->numEdges; t++ )
  {
    LWT_ISO_EDGE *e = &(splitNodeEdges->edges[t]);
    GEOSGeometry *eg;
    if ( e == existingEdge ) continue;
    if ( e == edge ) continue;
    if ( ! motionPolyG ) {
      motionPolyG = LWGEOM2GEOS( motionPoly, 0 );
      if ( ! motionPolyG )
      {
        lwerror("Could not convert edge geometry to GEOS: %s", lwgeom_geos_errmsg);
        return -1;
      }
    }
    eg = LWGEOM2GEOS( lwline_as_lwgeom(e->geom), 0 );
    if ( ! eg )
    {
      GEOSGeom_destroy(motionPolyG);
      lwgeom_free(motionPoly);
      lwerror("Could not convert edge geometry to GEOS: %s", lwgeom_geos_errmsg);
      return -1;
    }
 
    char *relate = GEOSRelate( motionPolyG, eg );
    GEOSGeom_destroy(eg);
    if ( ! relate )
    {
      GEOSGeom_destroy(motionPolyG);
      lwgeom_free(motionPoly);
      lwerror("Relate error: %s", lwgeom_geos_errmsg);
      return -1;
    }
 
    int match = GEOSRelatePatternMatch(relate, "FF*F*****");
    GEOSFree( relate );
    if (match == 2)
    {
      GEOSGeom_destroy(motionPolyG);
      lwgeom_free(motionPoly);
      lwerror("RelateMatch error: %s", lwgeom_geos_errmsg);
      return -1;
    }
    if ( ! match )
    {
      GEOSGeom_destroy(motionPolyG);
      lwgeom_free(motionPoly);
      lwerror("snapping edge %" LWTFMT_ELEMID
        " to new node moves it past edge %" LWTFMT_ELEMID,
        edge->edge_id, e->edge_id
      );
      return -1;
    }
  }
  if ( motionPolyG ) GEOSGeom_destroy(motionPolyG);
 
  lwgeom_free(motionPoly);
 
  return 0;
}

References LWT_ISO_EDGE::edge_id, LWT_NODE_EDGES_t::edges, LWT_ISO_EDGE::geom, LWCOLLECTION::geoms, LWDEBUGG, lwerror(), LWGEOM2GEOS(), lwgeom_as_lwline(), lwgeom_free(), lwgeom_geos_errmsg, lwgeom_make_valid(), lwline_as_lwgeom(), lwline_construct(), lwpoly_from_lwlines(), LWTFMT_ELEMID, LWT_NODE_EDGES_t::numEdges, LWLINE::points, ptarray_append_ptarray(), ptarray_clone_deep(), ptarray_free(), ptarray_reverse_in_place(), and LWT_TOPOLOGY_T::srid.

Referenced by _lwt_SnapEdgeToExistingNode().

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