1 / 17

2009. April. 01 Yongsu Song PNU STEM Lab

The Quadtree and Related Hierarchical Data Structures HANAN SAMET Computer Science Department, University of Maryland, College Park, Maryland 20742. 2009. April. 01 Yongsu Song PNU STEM Lab. Plan. Part 1 : Overview of Quadtree Part 2 : Basic Operation Start, Merge, Split, Group

jelani-norman
Download Presentation

2009. April. 01 Yongsu Song PNU STEM Lab

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Quadtree and Related Hierarchical Data StructuresHANAN SAMET Computer Science Department, University of Maryland, College Park, Maryland 20742 2009. April. 01 Yongsu Song PNU STEM Lab

  2. Plan • Part 1 : Overview of Quadtree • Part 2 : Basic Operation • Start, Merge, Split, Group • Example of tiling • Rope and Net • Part 3 : Alternates of Quadtree • Octree • K-d tree • Approximation Methods • Part 4 : Conclusion

  3. Overview of Quadtree Recursive decomposition. Similar to divide and conquer Geographic Information System, Image processing and so on..

  4. Cont. B F G H I 37 38 J N O 39 40 57 58 L Q M 59 60 A C D E B F G H I J K L M N O P Q 37 38 39 40 57 58 59 60

  5. 2. Basic OperationStart, Merge, Split, Group

  6. Example of tiling • Uniform orientation • Easy to implement Yamaguchi et al. [1984] Triangular quadtree to generate an isometric view from octree. (3D)

  7. Rope and Net B F G Rope : Link between two adjacent nodes of equal size where at least one of them is a leaf node. H I 37 38 J N O 39 40 Net : Linked list whose elements are all the nodes that are adjacent along a given side of a node. 57 58 L Q M 59 60 Fast! But.. A C D E B F G H I J K L M N O P Q 37 38 39 40 57 58 59 60

  8. Alternates of Quadtreek-d tree Quadtree K-d tree Fewer leaf nodes : 4 sons -> 2 sons Good at higher dimensional data!

  9. Point quadtree vs k-d tree Quadtree 2^k branching factor for k dimension k-d tree

  10. Approximation Methods Good : High resolution levels to low resolution. Bad : Comparing similar shapes. • Image approximation. • Shape approximation.

  11. Octree Is it possible? Structure to store the volume element

  12. Cont. 3 7 2 5 1 5 0 2 7 5 Stair case

  13. Curvilinear Data More complex? Boundaries of regions? Strip tree

  14. Cont. So what? • Special case • Closed curve by strip tree. • Extends past its endpoints.

  15. Cont. Null Clear. Possible • Intersecting two strip trees. • Curve approximation.

  16. Conclusion • The main idea • Recursive decomposition • Efficient For Region and Point • Divide and conquer • Reduce size range of target data • Important of data structure • Apply Approximation skills

  17. Cont. Any questions?

More Related