public static HashSet <uint> Search(this GeometricGraph graph, int n, float minLatitude, float minLongitude, float maxLatitude, float maxLongitude)
{
List <long> longList = HilbertCurve.HilbertDistances(System.Math.Max(minLatitude, -90f), System.Math.Max(minLongitude, -180f), System.Math.Min(maxLatitude, 90f), System.Math.Min(maxLongitude, 180f), (long)n);
longList.Sort();
HashSet <uint> uintSet = new HashSet <uint>();
int index = 0;
uint vertex1 = 0;
uint vertex2 = graph.VertexCount - 1U;
for (; index < longList.Count && vertex1 < graph.VertexCount; ++index)
{
long num1 = longList[index];
long maxHilbert;
for (maxHilbert = num1; index < longList.Count - 1 && longList[index + 1] <= maxHilbert + 1L; ++index)
{
maxHilbert = longList[index + 1];
}
uint vertex;
int count;
float latitude;
float longitude;
if (num1 == maxHilbert)
{
if (graph.Search(num1, n, vertex1, vertex2, out vertex, out count))
{
int num2 = count;
for (; count > 0; --count)
{
if (graph.GetVertex(vertex + (uint)(count - 1), out latitude, out longitude) && (double)minLatitude < (double)latitude && ((double)minLongitude < (double)longitude && (double)maxLatitude > (double)latitude) && (double)maxLongitude > (double)longitude)
{
uintSet.Add(vertex + (uint)(count - 1));
}
}
vertex1 = vertex + (uint)num2;
}
}
else if (graph.SearchRange(num1, maxHilbert, n, vertex1, vertex2, out vertex, out count))
{
int num2 = count;
for (; count > 0; --count)
{
if (graph.GetVertex(vertex + (uint)(count - 1), out latitude, out longitude) && (double)minLatitude < (double)latitude && ((double)minLongitude < (double)longitude && (double)maxLatitude > (double)latitude) && (double)maxLongitude > (double)longitude)
{
uintSet.Add(vertex + (uint)(count - 1));
}
}
vertex1 = vertex + (uint)num2;
}
}
return(uintSet);
}
/// <summary>
/// Searches the graph for nearby vertices assuming it has been sorted.
/// </summary>
/// <typeparam name="TEdgeData"></typeparam>
public static List <uint> SearchHilbert <TEdgeData>(this GraphBase <TEdgeData> graph, int n, float latitude, float longitude,
float offset)
where TEdgeData : struct, IGraphEdgeData
{
var targets = HilbertCurve.HilbertDistances(
System.Math.Max(latitude - offset, -90),
System.Math.Max(longitude - offset, -180),
System.Math.Min(latitude + offset, 90),
System.Math.Min(longitude + offset, 180), n);
targets.Sort();
var vertices = new List <uint>();
var targetIdx = 0;
var vertex1 = (uint)1;
var vertex2 = (uint)graph.VertexCount;
float vertexLat, vertexLon;
while (targetIdx < targets.Count)
{
uint vertex;
int count;
if (GraphExtensions.SearchHilbert(graph, targets[targetIdx], n, vertex1, vertex2, out vertex, out count))
{ // the search was successful.
while (count > 0)
{ // there have been vertices found.
if (graph.GetVertex((uint)vertex + (uint)(count - 1), out vertexLat, out vertexLon))
{ // the vertex was found.
if (System.Math.Abs(latitude - vertexLat) < offset &&
System.Math.Abs(longitude - vertexLon) < offset)
{ // within offset.
vertices.Add((uint)vertex + (uint)(count - 1));
}
}
count--;
}
// update vertex1.
vertex1 = vertex;
}
// move to next target.
targetIdx++;
}
return(vertices);
}
public void TestHilbertDistances1()
{
var distances = HilbertCurve.HilbertDistances(-90, -180, 90, 180, 2);
var expectedDistances = new long[] { 0, 1, 2, 3 };
Assert.AreEqual(expectedDistances.Length, distances.Count);
foreach (var expectedDistance in expectedDistances)
{
Assert.IsTrue(distances.Remove(expectedDistance));
}
Assert.AreEqual(0, distances.Count);
distances = HilbertCurve.HilbertDistances(-90, -180, 90, 180, 4);
expectedDistances = new long[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
Assert.AreEqual(expectedDistances.Length, distances.Count);
foreach (var expectedDistance in expectedDistances)
{
Assert.IsTrue(distances.Remove(expectedDistance));
}
Assert.AreEqual(0, distances.Count);
}