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I would like to find out a Locality Sensitive Hashing algorithm in order to split my spatial data into a number of buckets(reducer tasks). The spatial data are actually trajectories so from my understating of LSH a trajectory will be represented a set of 2d points.

Thanks, Adam

Adam
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1 Answers1

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Most probably you want a QuadTree:

"Quadtrees are most often used to partition a two-dimensional space by recursively subdividing it into four quadrants or regions."

You could store the actual points in a quadtree, and define trajectories as lists of indices referencing points in the quadtree.

heltonbiker
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  • I have found a geohashing library which encodes the latlon into a string and vice versa. – Adam Oct 15 '14 at 14:19
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    And which one it is? How does it work? Would you mind posting an answer so that other people might solve the same problem? – heltonbiker Oct 15 '14 at 14:25
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    This library https://github.com/kungfoo/geohash-java wrap up the core library that i have used. Am working now on these things. I will answer it in a later stage when i sum up things. – Adam Oct 16 '14 at 06:42
  • Fine. I have a strong (hobbyist) interest in these topics ("computational geography", so to say), if you want to chat about it, my e-mail is at my SO profile page! – heltonbiker Oct 16 '14 at 12:48
  • i cannot see your email – Adam Oct 16 '14 at 13:17
  • Sorry, I'm gonna check it, but its heltonbiker at gmail dot com. Thanks for your interest! – heltonbiker Oct 16 '14 at 13:34