TBQuadTree

Installing

pod 'TBQuadTree', '~> 0.0'

or you can just drag the source code into your project.

How to use

The quad tree is composed of TBQuadTreeNodeData structs:

typedef struct TBQuadTreeNodeData {
    double x;
    double y;
    void* data;
} TBQuadTreeNodeData;
TBQuadTreeNodeData TBQuadTreeNodeDataMake(double x, double y, void* data);

The void* data is a generic pointer which you can use to store additional information.

Here is an example quad tree made with random data:

double TBRandomRange(double low, double high)
{
    return ((double)arc4random() / 0x100000000) * (high - low) + low;
}

TBQuadTreeNode* TBBuildRandomQuadTree() 
{
  int points = 1E6;
  TBQuadTreeNodeData *data = malloc(sizeof(TBQuadTreeNodeData) * points); 
  for (int i = 0; i < points; i++) {
    TBQuadTreeNodeDataMake(TBRandomRange(0, 320), TBRandomRange(0, 320), NULL);
  }

  TBBoundingBox world = TBBoundingBoxMake(0, 0, 320, 320);
  TBQuadTreeNode *root = TBQuadTreeBuildWithData(data, points, world, 4);

  return root;
}

To query the quad tree use TBQuadTreeGatherDataInRange

void exampleQuery(TBQuadTreeNode* quadTree)
{
    TBBoundingBox queryBoundingBox = TBBoundingBoxMake(34.2, 28.1, 38.2, 33);
    TBQuadTreeGatherDataInRange(quadTree, queryBoundingBox, ^(TBQuadTreeNodeData data) {
      NSLog(@"Coordinate: (%F, %F)", data.x, data.y);
    }
}

Example project

If you want to learn more about how this data structure works check out my blog post

you can also see it in action in TBAnnotationClustering