/// <summary>
/// Starts pre-processing all nodes.
/// </summary>
public void Start()
{
// build the empty coordinate list.
var emptyCoordinateList = new GeoCoordinateSimple[0];
var verticesList = new HashSet <uint>();
// initialize status variables.
uint nextToProcess = 0;
uint nextPosition = 0;
// search edge until a real node.
double latestProgress = 0;
while (nextToProcess < _graph.VertexCount)
{ // keep looping until all vertices have been processed.
// select a new vertext to select.
var vertexToProcess = nextToProcess;
var edges = _graph.GetEdges(vertexToProcess).ToList();
if (edges.Count == 2)
{ // find one of the neighbours that is usefull.
vertexToProcess = edges[0].Neighbour;
edges = _graph.GetEdges(vertexToProcess).ToList();
verticesList.Clear();
verticesList.Add(vertexToProcess);
while (edges.Count == 2)
{ // keep looping until there is a vertex that is usefull.
vertexToProcess = edges[0].Neighbour;
if (verticesList.Contains(vertexToProcess))
{ // take the other vertex.
vertexToProcess = edges[1].Neighbour;
if (verticesList.Contains(vertexToProcess))
{ // an island was detected with only vertices having two neighbours.
// TODO: find a way to handle this!
edges = new List <Edge <Edge> >(0);
break;
}
}
verticesList.Add(vertexToProcess);
edges = _graph.GetEdges(vertexToProcess).ToList();
}
}
if (edges.Count > 0)
{ // ok, the vertex was not already processed.
nextPosition++;
var oldEdges = new List <Edge <Edge> >(edges);
var ignoreList = new HashSet <uint>();
foreach (var oldEdge in oldEdges)
{
if (ignoreList.Contains(oldEdge.Neighbour))
{ // ignore this edge: already removed in a previous iteration.
break;
}
// don't re-process edges that already have coordinates.
ICoordinateCollection oldEdgeValueCoordinates;
_graph.GetEdgeShape(vertexToProcess, oldEdge.Neighbour, out oldEdgeValueCoordinates);
if (oldEdgeValueCoordinates != null)
{ // this edge has already been processed.
break;
}
// STEP1: Build list of vertices that are only for form.
// set current/previous.
var distance = oldEdge.EdgeData.Distance;
var current = oldEdge.Neighbour;
var previous = vertexToProcess;
// build list of vertices.
var vertices = new List <uint>();
vertices.Add(previous);
vertices.Add(current);
// get next edges list.
var nextEdges = _graph.GetEdges(current).ToList();
while (nextEdges.Count == 2)
{ // ok the current vertex can be removed.
var nextEdge = nextEdges[0];
if (nextEdge.Neighbour == previous)
{ // it's the other edge!
nextEdge = nextEdges[1];
}
// compare edges.
if (nextEdge.EdgeData.Forward != oldEdge.EdgeData.Forward ||
nextEdge.EdgeData.Tags != oldEdge.EdgeData.Tags)
{ // oeps, edges are different!
break;
}
// check for intermediates.
ICoordinateCollection nextEdgeValueCoordinates;
_graph.GetEdgeShape(current, nextEdge.Neighbour, out nextEdgeValueCoordinates);
if (nextEdgeValueCoordinates != null)
{ // oeps, there are intermediates already, this can occur when two osm-ways are drawn on top of eachother.
break;
}
// add distance.
distance = distance + nextEdge.EdgeData.Distance;
// set current/previous.
previous = current;
current = nextEdge.Neighbour;
vertices.Add(current);
// get next edges.
nextEdges = _graph.GetEdges(current).ToList();
}
// check if the edge contains intermediate points.
if (vertices.Count == 2)
{ // no intermediate points: add the empty coordinate list.
var oldEdgeValue = oldEdge.EdgeData;
// keep edges that already have intermediates.
ICoordinateCollection edgeToKeepValueCoordinates = null;
var edgesToKeep = new List <Tuple <uint, Edge, ICoordinateCollection> >();
foreach (var edgeToKeep in _graph.GetEdges(vertexToProcess).ToList())
{
edgeToKeepValueCoordinates = null;
if (edgeToKeep.Neighbour == oldEdge.Neighbour &&
_graph.GetEdgeShape(vertexToProcess, edgeToKeep.Neighbour, out edgeToKeepValueCoordinates))
{
edgesToKeep.Add(new Tuple <uint, Edge, ICoordinateCollection>(
edgeToKeep.Neighbour, edgeToKeep.EdgeData, edgeToKeepValueCoordinates));
}
}
// delete olds arcs.
_graph.RemoveEdge(vertexToProcess, oldEdge.Neighbour);
// add new arc.
if (oldEdgeValue.Forward)
{
_graph.AddEdge(vertexToProcess, oldEdge.Neighbour, oldEdgeValue, null);
}
else
{
_graph.AddEdge(vertexToProcess, oldEdge.Neighbour, (Edge)oldEdgeValue.Reverse(), null);
}
// add edges to keep.
foreach (var edgeToKeep in edgesToKeep)
{
_graph.AddEdge(vertexToProcess, edgeToKeep.Item1, edgeToKeep.Item2, edgeToKeep.Item3);
}
}
else
{ // intermediate points: build array.
// STEP2: Build array of coordinates.
var coordinates = new GeoCoordinateSimple[vertices.Count - 2];
float latitude, longitude;
for (int idx = 1; idx < vertices.Count - 1; idx++)
{
_graph.GetVertex(vertices[idx], out latitude, out longitude);
coordinates[idx - 1] = new GeoCoordinateSimple()
{
Latitude = latitude,
Longitude = longitude
};
}
// STEP3: Remove all unneeded edges.
_graph.RemoveEdge(vertices[0], vertices[1]); // remove first edge.
for (int idx = 1; idx < vertices.Count - 1; idx++)
{ // delete all intermidiate arcs.
_graph.RemoveEdges(vertices[idx]);
}
_graph.RemoveEdge(vertices[vertices.Count - 1], vertices[vertices.Count - 2]); // remove last edge.
if (vertices[0] == vertices[vertices.Count - 1])
{ // also remove outgoing edge.
ignoreList.Add(vertices[vertices.Count - 2]); // make sure this arc is ignored in next iteration.
}
// STEP4: Add new edge.
if (oldEdge.EdgeData.Forward)
{
_graph.AddEdge(vertices[0], vertices[vertices.Count - 1], new Edge()
{
Forward = oldEdge.EdgeData.Forward,
Tags = oldEdge.EdgeData.Tags,
Distance = distance
}, new CoordinateArrayCollection <GeoCoordinateSimple>(coordinates));
}
else
{
var reverse = new GeoCoordinateSimple[coordinates.Length];
coordinates.CopyToReverse(reverse, 0);
_graph.AddEdge(vertices[vertices.Count - 1], vertices[0], new Edge()
{
Forward = !oldEdge.EdgeData.Forward,
Tags = oldEdge.EdgeData.Tags,
Distance = distance
}, new CoordinateArrayCollection <GeoCoordinateSimple>(reverse));
}
}
}
}
// move to the next position.
nextToProcess++;
// report progress.
float progress = (float)System.Math.Round((((double)nextToProcess / (double)_graph.VertexCount) * 100));
if (progress != latestProgress)
{
OsmSharp.Logging.Log.TraceEvent("Preprocessor", TraceEventType.Information,
"Removing edges... {0}%", progress);
latestProgress = progress;
}
}
// compress the graph.
this.CompressGraph();
}