/// <summary>
/// Compresses the graph by deleting vertices.
/// </summary>
private void CompressGraph()
{
// initialize status variables.
uint vertex = 1;
uint nextCompressedPosition = 1;
// search edge until a real node.
float latitude, longitude;
float latestProgress = -1;
while (vertex <= _graph.VertexCount)
{
var edges = _graph.GetEdges(vertex).ToList();
if (edges != null && edges.Count > 0)
{ // ok, this vertex has edges.
if (nextCompressedPosition != vertex)
{ // this vertex should go in another place.
_graph.GetVertex(vertex, out latitude, out longitude);
// set the next coordinates.
_graph.SetVertex(nextCompressedPosition, latitude, longitude);
// set the new edges.
_graph.RemoveEdges(nextCompressedPosition);
foreach (var edge in edges)
{ // add all arcs.
if (edge.Neighbour != vertex)
{ // this edge is not an edge that has the same end-start point.
if (edge.EdgeData.Forward)
{
_graph.AddEdge(nextCompressedPosition, edge.Neighbour, edge.EdgeData, null);
}
else
{
_graph.AddEdge(nextCompressedPosition, edge.Neighbour, (Edge)edge.EdgeData.Reverse(), null);
}
}
else
{ // this edge is an edge that has the same end-start point.
_graph.AddEdge(nextCompressedPosition, nextCompressedPosition, edge.EdgeData, null);
}
// update other arcs.
if (edge.Neighbour != vertex)
{ // do not update other arcs if other vertex is the same.
var reverseEdges = _graph.GetEdges(edge.Neighbour).ToList();
if (reverseEdges != null)
{ // there are reverse edges, check if there is a reference to vertex.
reverseEdges = new List <Edge <Edge> >(reverseEdges);
foreach (var reverseEdge in reverseEdges)
{ // check each edge for vertex.
if (reverseEdge.Neighbour == vertex)
{ // ok, replace this edge.
ICoordinateCollection reverseEdgeCoordinates;
if (!_graph.GetEdgeShape(edge.Neighbour, reverseEdge.Neighbour, out reverseEdgeCoordinates))
{
reverseEdgeCoordinates = null;
}
_graph.RemoveEdge(edge.Neighbour, vertex);
if (reverseEdgeCoordinates == null)
{
_graph.AddEdge(edge.Neighbour, nextCompressedPosition, (Edge)reverseEdge.EdgeData.Reverse(), null);
}
else if (reverseEdge.EdgeData.Forward)
{
_graph.AddEdge(edge.Neighbour, nextCompressedPosition, reverseEdge.EdgeData, reverseEdgeCoordinates);
}
else
{
_graph.AddEdge(edge.Neighbour, nextCompressedPosition, (Edge)reverseEdge.EdgeData.Reverse(), reverseEdgeCoordinates.Reverse());
}
}
}
}
}
}
}
nextCompressedPosition++;
}
// move to the next vertex.
vertex++;
// report progress.
float progress = (float)System.Math.Round((((double)vertex / (double)_graph.VertexCount) * 100));
if (progress != latestProgress)
{
OsmSharp.Logging.Log.TraceEvent("Preprocessor", TraceEventType.Information,
"Compressing graph... {0}%", progress);
latestProgress = progress;
}
}
// remove all extra space.
_graph.Compress();
_graph.Trim();
}