title: Any good range Query library(using K-D tree, quad tree or R-tree) in C++
body: <p>I used this library before <a href="http://www.cs.umd.edu/~mount/ANN/" rel="nofollow">http://www.cs.umd.edu/~mount/ANN/</a>. However, they don't provide range query implementations. I Guess is there a C++ range-query implementation (Both circle or rectangle), to query two-dimensional data.</p>
  
  <p>Thanks.</p>