/// <summary>
/// Saves a node to a stream recursively
/// </summary>
/// <param name="node">Node to save</param>
/// <param name="sw">Reference to BinaryWriter</param>
private void SaveNode(QuadTreeOld node, ref System.IO.BinaryWriter sw)
{
//Write node boundingbox
sw.Write(node.Box.MinX);
sw.Write(node.Box.MinY);
sw.Write(node.Box.MaxX);
sw.Write(node.Box.MaxY);
sw.Write(node.IsLeaf);
if (node.IsLeaf)
{
sw.Write(node._objList.Count); //Write number of features at node
for (int i = 0; i < node._objList.Count; i++) //Write each featurebox
{
sw.Write(node._objList[i].box.MinX);
sw.Write(node._objList[i].box.MinY);
sw.Write(node._objList[i].box.MaxX);
sw.Write(node._objList[i].box.MaxY);
sw.Write(node._objList[i].ID);
}
}
else if (!node.IsLeaf) //Save next node
{
SaveNode(node.Child0, ref sw);
SaveNode(node.Child1, ref sw);
}
}
/// <summary>
/// Disposes the node
/// </summary>
public void Dispose()
{
//this._box = null;
this._child0 = null;
this._child1 = null;
this._objList = null;
}
/// <summary>
/// Reads a node from a stream recursively
/// </summary>
/// <param name="depth">Current depth</param>
/// <param name="br">Binary reader reference</param>
/// <returns></returns>
private static QuadTreeOld ReadNode(uint depth, ref System.IO.BinaryReader br)
{
QuadTreeOld node = new QuadTreeOld();
node._Depth = depth;
node.Box = GeometryFactory.CreateEnvelope(br.ReadDouble(), br.ReadDouble(), br.ReadDouble(), br.ReadDouble());
bool IsLeaf = br.ReadBoolean();
if (IsLeaf)
{
int FeatureCount = br.ReadInt32();
node._objList = new List <BoxObjects>();
for (int i = 0; i < FeatureCount; i++)
{
BoxObjects box = new BoxObjects();
box.box = GeometryFactory.CreateEnvelope(br.ReadDouble(), br.ReadDouble(), br.ReadDouble(), br.ReadDouble());
box.ID = (uint)br.ReadInt32();
node._objList.Add(box);
}
}
else
{
node.Child0 = ReadNode(node._Depth + 1, ref br);
node.Child1 = ReadNode(node._Depth + 1, ref br);
}
return(node);
}
/// <summary>
/// Loads a quadtree from a file
/// </summary>
/// <param name="filename"></param>
/// <returns></returns>
public static QuadTreeOld FromFile(string filename)
{
System.IO.FileStream fs = new System.IO.FileStream(filename, System.IO.FileMode.Open, System.IO.FileAccess.Read);
System.IO.BinaryReader br = new System.IO.BinaryReader(fs);
if (br.ReadDouble() != INDEXFILEVERSION) //Check fileindex version
{
fs.Close();
fs.Dispose();
throw new ObsoleteFileFormatException("Invalid index file version. Please rebuild the spatial index by either deleting the index");
}
QuadTreeOld node = ReadNode(0, ref br);
br.Close();
fs.Close();
return(node);
}
/// <summary>
/// Recursive function that traverses the tree and looks for intersections with a boundingbox
/// </summary>
/// <param name="box">Boundingbox to intersect with</param>
/// <param name="node">Node to search from</param>
/// <param name="list">List of found intersections</param>
private void IntersectTreeRecursive(IEnvelope box, QuadTreeOld node, ref Collection <int> list)
{
if (node.IsLeaf) //Leaf has been reached
{
for (int i = 0; i < node._objList.Count; i++)
{
list.Add((int)node._objList[i].ID);
}
}
else
{
if (node.Box.Intersects(box))
{
IntersectTreeRecursive(box, node.Child0, ref list);
IntersectTreeRecursive(box, node.Child1, ref list);
}
}
}
/// <summary>
/// Creates a node and either splits the objects recursively into sub-nodes, or stores them at the node depending on the heuristics.
/// Tree is built top->down
/// </summary>
/// <param name="objList">Geometries to index</param>
/// <param name="depth">Current depth of tree</param>
/// <param name="heurdata">Heuristics data</param>
public QuadTreeOld(List <BoxObjects> objList, uint depth, Heuristic heurdata)
{
_Depth = depth;
_box = new Envelope(objList[0].box);
for (int i = 0; i < objList.Count; i++)
{
_box.ExpandToInclude(objList[i].box);
}
// test our build heuristic - if passes, make children
if (depth < heurdata.maxdepth && objList.Count > heurdata.mintricnt &&
(objList.Count > heurdata.tartricnt || ErrorMetric(_box) > heurdata.minerror))
{
List <BoxObjects>[] objBuckets = new List <BoxObjects> [2]; // buckets of geometries
objBuckets[0] = new List <BoxObjects>();
objBuckets[1] = new List <BoxObjects>();
string longaxis = LongestAxis(_box); // longest axis
double geoavg = 0; // geometric average - midpoint of ALL the objects
// go through all bbox and calculate the average of the midpoints
double frac = 1.0f / objList.Count;
for (int i = 0; i < objList.Count; i++)
{
if (longaxis == "X")
{
geoavg += objList[i].box.Centre.X * frac;
}
else
{
geoavg += objList[i].box.Centre.Y * frac;
}
}
// // bucket bbox based on their midpoint's side of the geo average in the longest axis
for (int i = 0; i < objList.Count; i++)
{
if (longaxis == "X")
{
objBuckets[geoavg > objList[i].box.Centre.X ? 1 : 0].Add(objList[i]);
}
else
{
objBuckets[geoavg > objList[i].box.Centre.Y ? 1 : 0].Add(objList[i]);
}
}
//If objects couldn't be splitted, just store them at the leaf
//TODO: Try splitting on another axis
if (objBuckets[0].Count == 0 || objBuckets[1].Count == 0)
{
_child0 = null;
_child1 = null;
// copy object list
_objList = objList;
}
else
{
// create new children using the buckets
_child0 = new QuadTreeOld(objBuckets[0], depth + 1, heurdata);
_child1 = new QuadTreeOld(objBuckets[1], depth + 1, heurdata);
}
}
else
{
// otherwise the build heuristic failed, this is
// set the first child to null (identifies a leaf)
_child0 = null;
_child1 = null;
// copy object list
_objList = objList;
}
}
/// <summary>
/// Creates a node and either splits the objects recursively into sub-nodes, or stores them at the node depending on the heuristics.
/// Tree is built top->down
/// </summary>
/// <param name="objList">Geometries to index</param>
/// <param name="depth">Current depth of tree</param>
/// <param name="heurdata">Heuristics data</param>
public QuadTreeOld(List<BoxObjects> objList, uint depth, Heuristic heurdata)
{
_Depth = depth;
_box = new Envelope(objList[0].box);
for (int i = 0; i < objList.Count;i++ )
_box.ExpandToInclude(objList[i].box);
// test our build heuristic - if passes, make children
if (depth < heurdata.maxdepth && objList.Count > heurdata.mintricnt &&
(objList.Count > heurdata.tartricnt || ErrorMetric(_box) > heurdata.minerror))
{
List<BoxObjects>[] objBuckets = new List<BoxObjects>[2]; // buckets of geometries
objBuckets[0] = new List<BoxObjects>();
objBuckets[1] = new List<BoxObjects>();
string longaxis = LongestAxis(_box); // longest axis
double geoavg = 0; // geometric average - midpoint of ALL the objects
// go through all bbox and calculate the average of the midpoints
double frac = 1.0f / objList.Count;
for (int i = 0; i < objList.Count;i++ )
{
if (longaxis=="X")
geoavg += objList[i].box.Centre.X * frac;
else
geoavg += objList[i].box.Centre.Y * frac;
}
// // bucket bbox based on their midpoint's side of the geo average in the longest axis
for (int i = 0; i < objList.Count;i++ )
{
if(longaxis=="X")
objBuckets[geoavg > objList[i].box.Centre.X ? 1 : 0].Add(objList[i]);
else
objBuckets[geoavg > objList[i].box.Centre.Y ? 1 : 0].Add(objList[i]);
}
//If objects couldn't be splitted, just store them at the leaf
//TODO: Try splitting on another axis
if (objBuckets[0].Count == 0 || objBuckets[1].Count == 0)
{
_child0 = null;
_child1 = null;
// copy object list
_objList = objList;
}
else
{
// create new children using the buckets
_child0 = new QuadTreeOld(objBuckets[0], depth + 1, heurdata);
_child1 = new QuadTreeOld(objBuckets[1], depth + 1, heurdata);
}
}
else
{
// otherwise the build heuristic failed, this is
// set the first child to null (identifies a leaf)
_child0 = null;
_child1 = null;
// copy object list
_objList = objList;
}
}
/// <summary>
/// Recursive function that traverses the tree and looks for intersections with a boundingbox
/// </summary>
/// <param name="box">Boundingbox to intersect with</param>
/// <param name="node">Node to search from</param>
/// <param name="list">List of found intersections</param>
private void IntersectTreeRecursive(IEnvelope box, QuadTreeOld node, ref Collection<int> list)
{
if (node.IsLeaf) //Leaf has been reached
{
for (int i = 0; i < node._objList.Count; i++)
{
list.Add((int) node._objList[i].ID);
}
}
else
{
if(node.Box.Intersects(box))
{
IntersectTreeRecursive(box, node.Child0, ref list);
IntersectTreeRecursive(box, node.Child1, ref list);
}
}
}
/// <summary>
/// Disposes the node
/// </summary>
public void Dispose()
{
//this._box = null;
this._child0 = null;
this._child1 = null;
this._objList = null;
}
/// <summary>
/// Saves a node to a stream recursively
/// </summary>
/// <param name="node">Node to save</param>
/// <param name="sw">Reference to BinaryWriter</param>
private void SaveNode(QuadTreeOld node, ref System.IO.BinaryWriter sw)
{
//Write node boundingbox
sw.Write(node.Box.MinX);
sw.Write(node.Box.MinY);
sw.Write(node.Box.MaxX);
sw.Write(node.Box.MaxY);
sw.Write(node.IsLeaf);
if (node.IsLeaf)
{
sw.Write(node._objList.Count); //Write number of features at node
for (int i = 0; i < node._objList.Count;i++ ) //Write each featurebox
{
sw.Write(node._objList[i].box.MinX);
sw.Write(node._objList[i].box.MinY);
sw.Write(node._objList[i].box.MaxX);
sw.Write(node._objList[i].box.MaxY);
sw.Write(node._objList[i].ID);
}
}
else if (!node.IsLeaf) //Save next node
{
SaveNode(node.Child0, ref sw);
SaveNode(node.Child1, ref sw);
}
}
/// <summary>
/// Reads a node from a stream recursively
/// </summary>
/// <param name="depth">Current depth</param>
/// <param name="br">Binary reader reference</param>
/// <returns></returns>
private static QuadTreeOld ReadNode(uint depth, ref System.IO.BinaryReader br)
{
QuadTreeOld node = new QuadTreeOld();
node._Depth = depth;
node.Box = GeometryFactory.CreateEnvelope(br.ReadDouble(),br.ReadDouble(),br.ReadDouble(),br.ReadDouble());
bool IsLeaf = br.ReadBoolean();
if (IsLeaf)
{
int FeatureCount = br.ReadInt32();
node._objList = new List<BoxObjects>();
for (int i = 0; i < FeatureCount; i++)
{
BoxObjects box = new BoxObjects();
box.box = GeometryFactory.CreateEnvelope(br.ReadDouble(), br.ReadDouble(), br.ReadDouble(), br.ReadDouble());
box.ID = (uint)br.ReadInt32();
node._objList.Add(box);
}
}
else
{
node.Child0 = ReadNode(node._Depth + 1, ref br);
node.Child1 = ReadNode(node._Depth + 1, ref br);
}
return node;
}
