Here you will find source codes for the original R-tree and some of its most popular variants (R+-tree, R*-tree, ...), mainly used for indexing data in low-dimensional space, R-tree extensions for high-dimensional spaces (TV-tree, X-tree, ...), and R-tree-based indexing techniques for temporal and spatio-temporal data (Segment R-tree, TB-tree, ...).

Last but not least, links to libraries for programming purposes.(GiST, XXL etc.)