Talk:Quadtree

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[edit] Leaf, having no children?

Thanks to the editors who wrote this article. I think the end of the sentence, "A point region (PR) quadtree is a type of quadtree where each node must have exactly four children, or leaf, having no children." could be clearer, though. Could someone who knows the subject clarify what's meant here? Thanks! --Allen 02:54, 9 March 2006 (UTC)

The author probably meant: A point region quadtree is a type of quadtree where each node either has exactly four children, or none. A node with no children is called a leaf.

However, that would define a full or proper quadtree, rather than explain why or how such a tree is used as a region or point region quadtree. -- Gimmetrow 03:49, 4 May 2006 (UTC)

[edit] Is the Tree in the picture really a Point Tree?

"The point quadtree is an adaptation of a binary tree used to represent two dimensional point data. It shares the features of all quadtrees but is a true tree as the centre of a subdivision is always on a point." The tree in the picture looks rather like a Region Tree to me, but I'm not really sure... —Preceding unsigned comment added by 85.0.157.176 (talk) 16:25, 6 February 2008 (UTC)

I believe you're correct. A point quadtree would only subdivide around an existing point in the dataset - the uniform divisions shown in the image sound more like a region tree according to the definitions in this article. I'd like someone else to double-check this though before we change it. Dcoetzee 19:48, 6 February 2008 (UTC)