title: Understanding boost spatial index queries documentation
body: <p>I have trouble understanding queries in <a href="https://www.boost.org/doc/libs/1_77_0/libs/geometry/doc/html/geometry/spatial_indexes/queries.html" rel="nofollow noreferrer">Boost geometry spatial index documentation</a></p>
  <p>My understanding is that the red and green rectangles are not actually part of the data but symbolize internal nodes in the tree structure ? And that the black rectangles are actual data ?</p>
  <h1>intersects(Box)</h1>
  <p><a href="https://i.stack.imgur.com/Q6q93.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Q6q93.png" alt="intersects(Box)" /></a></p>
  <p>Assuming the Box in question is the biggest orange one, why are there 6 resulting small orange boxes, not just 2 (the two uppermost ones) ?</p>
  <h1>overlaps(Box)</h1>
  <p><a href="https://i.stack.imgur.com/npVZv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/npVZv.png" alt="overlaps(Box)" /></a></p>
  <p>Assuming the Box in question is the biggest orange one, why are there 3 black bloxes inside ? They seem to overlap with the biggest orange one, so I would assume they are orange (= part of the results).</p>
  <h1>covered_by(Box)  and  within(Box)</h1>
  <p>What is the difference between these two functions ? The pictures seem exactly identical.</p>