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The R* Tree : An Efficient and Robust Access Method for Points and Rectangles

The R* Tree : An Efficient and Robust Access Method for Points and Rectangles. Chapter 4. Data Storage and Access Methods. Team 2: Ravali Kandur Yash Khandelwal. Problem Statement. Given Data containing different geometries (points and rectangles)

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The R* Tree : An Efficient and Robust Access Method for Points and Rectangles

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  1. The R* Tree: An Efficient and Robust Access Method for Points and Rectangles Chapter 4. Data Storage and Access Methods Team 2: RavaliKandur Yash Khandelwal

  2. Problem Statement • Given • Data containing different geometries (points and rectangles) • Spatial queries (point, range query, insert, delete) • Find • An Access Method (Data Structure) that indexes spatial datasets • Ahierarchical collection of rectangles to organize spatial data • Objectives • Efficiency of spatial queries • Area, Margin, Overlap • Constraints • Balanced tree • Each node is a disk page and has >= m (min # of entries) entries. • Root has at least two children unless it is a leaf • Efficiency metric = number of disk-pages accessed

  3. Comparison of Family of R trees

  4. Example : R tree D R2 D1 D R1 R3 D2 D3 D1 R4 D3 D2 R7 R4, R5 R6, R7 R1, R2, R3 R5 R6

  5. Example : R+ tree D R2 D1 D R1 R3 D2 D3 D1 R4 D2 D3 R7 R5 R4, R5 R5, R6, R7 R1, R2, R3 R6

  6. Example : R* tree D D1 R2 D R1 D2 R3 D2 D3 D1 R4 D3 R7 R5 R3, R4, R5 R6, R7 R1, R2 R6

  7. R-Tree R+-Tree R*-Tree

  8. Comparison of Metrics

  9. References • Authors:N. Beckmann, H. Kriegel, R. Schneider and B. Seeger (Pages: 207-216) • http://en.wikipedia.org/wiki/R-tree • http://repository.cmu.edu/cgi/viewcontent.cgi?article=1563&context=compsci • http://en.wikipedia.org/wiki/R*_tree

  10. Questions?

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