/// <summary>
/// Calculating the Dijkstra distance
/// </summary>
/// <returns></returns>
public double GetAstarDistance(LocationTimeValue a, LocationTimeValue b, Mesh mesh)
{
double ret = 0;
try
{
TemporalMesh = new Mesh(mesh);
End = TemporalMesh.Vertices.OrderBy(x => GeographyHelper.EuclideanDistance(b, x)).First();
for (int i = 0; i < TemporalMesh.Vertices.Count(); i++)
{
//Preparing the mesh for distance storage
if (TemporalMesh.Vertices[i].Value.Count() == 1)
{
TemporalMesh.Vertices[i].Value.Add(0);
}
else if (TemporalMesh.Vertices[i].Value.Count() == 0)
{
TemporalMesh.Vertices[i].Value.AddRange(new List <double>()
{
0, 0
});
}
//Initializing the distances
TemporalMesh.Vertices[i].Value[0] = double.PositiveInfinity;
TemporalMesh.Vertices[i].Value[1] = End.GetEuclideanDistance(TemporalMesh.Vertices[i]);
TemporalMesh.Vertices[i].Neighbors = new List <LocationTimeValue>();
TemporalMesh.Vertices[i].IsActive = false;
}
Start = TemporalMesh.Vertices.OrderBy(x => GeographyHelper.EuclideanDistance(a, x)).First();
Start.Value[0] = 0;
End = TemporalMesh.Vertices.OrderBy(x => GeographyHelper.EuclideanDistance(b, x)).First();
if (Start.GetEuclideanDistance(End) == 0)
{
return(0);
}
//Building the shortest path
BuildShortestPathAstar();
ret = ShortestPathCost;
}
catch
{
}
return(ret);
}
/// <summary>
/// Building the shortest path
/// </summary>
/// <param name="list"></param>
/// <param name="node"></param>
private void BuildShortestPath(List <LocationTimeValue> list, LocationTimeValue node)
{
if (node.Neighbors.Count() == 0)
{
return;
}
LocationTimeValue nearestNeighbor = node.Neighbors.Where(x => x.Neighbors.Count > 0).First();
list.Add(nearestNeighbor);
ShortestPathLength += GeographyHelper.EuclideanDistance(nearestNeighbor, node);
ShortestPathCost += GeographyHelper.EuclideanDistance(nearestNeighbor, node);
nearestNeighbor.Neighbors.Remove(node);
if (nearestNeighbor.Equals(Start))
{
return;
}
BuildShortestPath(list, nearestNeighbor);
}
/// <summary>
/// Converts a hexahedron to a list of tetrahedons
/// </summary>
/// <returns></returns>
public List <Cell> ToTetrahedons(Mesh mesh)
{
//return object
List <Cell> ret = new List <Cell>();
try
{
LocationTimeValue[] vert = GetVertices(mesh);
CreateFaces(mesh);
LocationTimeValue loc1 = vert[0];
LocationTimeValue loc2 = vert.OrderByDescending(x => GeographyHelper.EuclideanDistance(x, loc1)).First();
for (int i = 0; i < Faces.Count(); i++)
{
Faces[i].Vertices.OrderBy(x => GeographyHelper.EuclideanDistance(x, Faces[i].Vertices[0]));
Tetrahedron tet = new Tetrahedron();
tet.Vertices = new List <int>()
{
mesh.Vertices.IndexOf(Faces[i].Vertices[0]),
mesh.Vertices.IndexOf(Faces[i].Vertices[1]),
mesh.Vertices.IndexOf(Faces[i].Vertices[2])
};
if (Faces[i].Vertices.Contains(loc1))
{
tet.Vertices.Add(mesh.Vertices.IndexOf(loc2));
}
else
{
tet.Vertices.Add(mesh.Vertices.IndexOf(loc1));
}
tet.CreateFaces(mesh);
tet = new Tetrahedron();
tet.Vertices = new List <int>()
{
mesh.Vertices.IndexOf(Faces[i].Vertices[3]),
mesh.Vertices.IndexOf(Faces[i].Vertices[1]),
mesh.Vertices.IndexOf(Faces[i].Vertices[2])
};
if (Faces[i].Vertices.Contains(loc1))
{
tet.Vertices.Add(mesh.Vertices.IndexOf(loc2));
}
else
{
tet.Vertices.Add(mesh.Vertices.IndexOf(loc1));
}
tet.CreateFaces(mesh);
ret.Add(tet);
}
}
catch
{
ret = new List <Cell>();
}
return(ret);
}
/// <summary>
/// Computing the IDW data matrix
/// </summary>
public void ComputeIDW()
{
if (OriginalLocationValues.Count < 1)
{
DiscretizedLocationValues = new List <LocationTimeValue <double> >();
DiscretizedLocationVariance = new List <LocationTimeValue <double> >();
}
List <LocationTimeValue <double> > ret = new List <LocationTimeValue <double> >();
double rmseSum = 0;
try
{
//Doing discretization if not done yet
if (!OriginalLocationValues.First().IsDiscretized)
{
DiscretizedLocationValues = new List <LocationTimeValue <double> >();
DiscretizedLocationVariance = new List <LocationTimeValue <double> >();
DiscretizeOriginalLocalLocationValuesIntoRegularGrid();
}
for (int i = 0; i < DiscretizedLocationValues.Count(); i++)
{
double value = 0;
double weightSum = 0;
//Calculating IDW values
for (int j = 0; j < OriginalLocationValues.Count(); j++)
{
double dist = GeographyHelper.EuclideanDistance(DiscretizedLocationValues[i].X - OriginalLocationValues[j].X, DiscretizedLocationValues[i].Y - OriginalLocationValues[j].Y, DiscretizedLocationValues[i].Z - OriginalLocationValues[j].Z, false);
if (dist != 0)
{
//Summing up the weights
weightSum += 1 / Math.Pow(dist, Power);
//Increasing the value by the constrain value and it's weight
value += Convert.ToDouble(OriginalLocationValues[j].Value) / Math.Pow(dist, Power);
}
else
{
value = OriginalLocationValues[j].Value;
break;
}
}
DiscretizedLocationValues[i].Value = value / weightSum;
}
//Calculating the RMSE
for (int i = 0; i < OriginalLocationValues.Count(); i++)
{
double weightSum = 0;
double value = 0;
for (int j = 0; j < OriginalLocationValues.Count(); j++)
{
if (i != j)
{
double dist = GeographyHelper.EuclideanDistance(DiscretizedLocationValues[i].X - OriginalLocationValues[j].X, DiscretizedLocationValues[i].Y - OriginalLocationValues[j].Y, DiscretizedLocationValues[i].Z - OriginalLocationValues[j].Z, false);
if (dist != 0)
{
weightSum += 1 / Math.Pow(dist, Power);
value += Convert.ToDouble(OriginalLocationValues[j].Value) / Math.Pow(dist, Power);
}
else
{
continue;
}
}
}
rmseSum += Math.Abs(Math.Pow(OriginalLocationValues[i].Value - (value / weightSum), 2));
}
RMSE = Math.Sqrt(rmseSum / OriginalLocationValues.Count());
}
catch
{
}
}
/// <summary>
/// Triangulates a surface
/// </summary>
/// <param name="points"></param>
/// <returns></returns>
public List <Face> TriangulateSurface(List <LocationTimeValue> inputVertices)
{
List <Face> mesh = new List <Face>();
try
{
// Important! Sort the list so that points sweep from left - right
inputVertices.Sort();
SqlGeometry MultiPoint = inputVertices.ToSqlGeometry();
// Calculate the "supertriangle" that encompasses the pointset
SqlGeometry Envelope = MultiPoint.STEnvelope();
// Width
double dx = (double)(Envelope.STPointN(2).STX - Envelope.STPointN(1).STX);
// Height
double dy = (double)(Envelope.STPointN(4).STY - Envelope.STPointN(1).STY);
// Maximum dimension
double dmax = (dx > dy) ? dx : dy;
// Centre
double avgx = (double)Envelope.STCentroid().STX;
double avgy = (double)Envelope.STCentroid().STY;
// Create the points at corners of the supertriangle
LocationTimeValue a = new LocationTimeValue(avgx - 2 * dmax, avgy - dmax);
LocationTimeValue b = new LocationTimeValue(avgx + 2 * dmax, avgy - dmax);
LocationTimeValue c = new LocationTimeValue(avgx, avgy + 2 * dmax);
Triangle superTriangle = new Triangle(a, b, c);
List <Triangle> Triangles = new List <Triangle>();
Triangles.Add(superTriangle);
// Loop through each point
Parallel.For(0, inputVertices.Count(), i =>
{
// Initialise the edge buffer
List <LocationTimeValue[]> Edges = new List <LocationTimeValue[]>();
try
{
// Loop through each triangle
for (int j = Triangles.Count - 1; j >= 0; j--)
{
// If the point lies within the circumcircle of this triangle
if (GeographyHelper.EuclideanDistance(Triangles[j].GetCircumCentre(), inputVertices[i]) <= Triangles[j].GetRadius())
{
// Add the triangle edges to the edge buffer
Edges.Add(new LocationTimeValue[] { Triangles[j].Vertices[0], Triangles[j].Vertices[1] });
Edges.Add(new LocationTimeValue[] { Triangles[j].Vertices[1], Triangles[j].Vertices[2] });
Edges.Add(new LocationTimeValue[] { Triangles[j].Vertices[2], Triangles[j].Vertices[0] });
// Remove this triangle from the list
Triangles.RemoveAt(j);
}
// If this triangle is complete
else if (inputVertices[i].X >= Triangles[j].GetCircumCentre().X + Triangles[j].GetRadius())
{
mesh.Add(Triangles[j]);
Triangles.RemoveAt(j);
}
}
// Remove duplicate edges
for (int j = Edges.Count - 1; j > 0; j--)
{
for (int k = j - 1; k >= 0; k--)
{
// Compare if this edge match in either direction
if (Edges[j][0].Equals(Edges[k][1]) && Edges[j][1].Equals(Edges[k][0]))
{
// Remove both duplicates
Edges.RemoveAt(j);
Edges.RemoveAt(k);
// We've removed an item from lower down the list than where j is now, so update j
j--;
break;
}
}
}
// Create new triangles for the current point
for (int j = 0; j < Edges.Count; j++)
{
Triangle T = new Triangle(Edges[j][0], Edges[j][1], inputVertices[i]);
Triangles.Add(T);
}
}
catch
{
}
});
mesh.AddRange(Triangles);
int count = mesh.Count();
//We've finished triangulation. Move any remaining triangles onto the completed list
for (int i = 0; i < count; i++)
{
if (mesh[i].Vertices.Any(x => superTriangle.Vertices.Contains(x)))
{
mesh.RemoveAt(i);
count--;
i--;
}
}
}
catch
{
}
return(mesh);
}
/// <summary>
/// Performing a A* search
/// </summary>
private void AstarSearch()
{
NodeVisits = 0;
//Initializing priority queue
var prioQueue = new List <LocationTimeValue>();
//Adding start point to the queue
prioQueue.Add(Start);
//Filling priority queue and iterating through it until break conditions are met
do
{
NodeVisits++;
//Order points by distance to start
prioQueue = prioQueue.OrderBy(x => x.Value[0] + x.Value[1]).ToList();
var node = prioQueue.First();
prioQueue.Remove(node);
//Getting the neighbors of the node
var neighbors = TemporalMesh.GetNeighbors(node).Result.OrderBy(x => GeographyHelper.EuclideanDistance(x, node)).ToList();
//Iterating over the neighbors and detect which one has the lowest distance to the node
for (int i = 0; i < neighbors.Count(); i++)
{
//Check that the point does not equals the node where we came from
if (node.Neighbors.Count > 0)
{
if (neighbors[i].Equals(node.Neighbors.First()))
{
continue;
}
}
//Determining the euclidean distance to the neighbor
double dist = GeographyHelper.EuclideanDistance(neighbors[i], node);
neighbors[i].Value[0] = node.Value[0] + dist;
if (neighbors[i].Neighbors.Count == 0 || !neighbors.Where(x => !x.Equals(node)).Any(x => x.Value[0] < neighbors[i].Value[0]))
{
//Setting the node as a neighbor
neighbors[i].Neighbors.Clear();
neighbors[i].Neighbors.Add(node);
//If the node equals the end, we reached our aim
if (node.Equals(End))
{
return;
}
//Adding node to the priority queue
if (!prioQueue.Contains(neighbors[i]))
{
prioQueue.Add(neighbors[i]);
}
}
}
//"Deactivating" the node that it will not be used again
node.IsActive = true;
} while (prioQueue.Any());
}