/// <summary>
/// Adds an Edge, DirectedEdges, and Nodes for the given LineString representation
/// of an edge.
/// </summary>
public void AddEdge(ILineString lineString)
{
if (lineString.IsEmpty)
{
return;
}
Coordinate[] coordinates = CoordinateArrays.RemoveRepeatedPoints(lineString.Coordinates);
if (coordinates.Length < 2)
{
return; // same check already added in PolygonizeGraph (see #87 and #146)
}
Coordinate startCoordinate = coordinates[0];
Coordinate endCoordinate = coordinates[coordinates.Length - 1];
Node startNode = GetNode(startCoordinate);
Node endNode = GetNode(endCoordinate);
DirectedEdge directedEdge0 = new LineMergeDirectedEdge(startNode, endNode,
coordinates[1], true);
DirectedEdge directedEdge1 = new LineMergeDirectedEdge(endNode, startNode,
coordinates[coordinates.Length - 2], false);
Edge edge = new LineMergeEdge(lineString);
edge.SetDirectedEdges(directedEdge0, directedEdge1);
Add(edge);
}
/// <summary>
/// Builds a geometry (<see cref="LineString" /> or <see cref="MultiLineString" />)
/// representing the sequence.
/// </summary>
/// <param name="sequences">
/// An enumeration of <see cref="IList{DirectedEdge}" />s of <see cref="DirectedEdge" />s
/// with <see cref="LineMergeEdge" />s as their parent edges.
/// </param>
/// <returns>
/// The sequenced geometry, or <c>null</c> if no sequence exists.
/// </returns>
private IGeometry BuildSequencedGeometry(IEnumerable <IEnumerable <DirectedEdge> > sequences)
{
IList <IGeometry> lines = new List <IGeometry>();
foreach (IList <DirectedEdge> seq in sequences)
{
foreach (DirectedEdge de in seq)
{
LineMergeEdge e = (LineMergeEdge)de.Edge;
ILineString line = e.Line;
ILineString lineToAdd = line;
if (!de.EdgeDirection && !line.IsClosed)
{
lineToAdd = Reverse(line);
}
lines.Add(lineToAdd);
}
}
return(lines.Count == 0 ? _factory.CreateMultiLineString(new ILineString[] { }) : _factory.BuildGeometry(lines));
}