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Re^2: Speeding up point-in-polygon -- take two (Under 40 seconds!)

by punkish (Priest)
on Aug 28, 2006 at 17:31 UTC ( #570016=note: print w/ replies, xml ) Need Help??


in reply to Re: Speeding up point-in-polygon -- take two (Under 40 seconds!)
in thread Speeding up point-in-polygon -- take two

> The following shows the output from several runs 
> of a benchmark looking up 5.25 million randomly 
> generated points in a coordinate space of 5000x5000 
> that contains 1/4 million polygons:
Ya but, are your polys regular? If so, that changes the whole game. It is because my polys are irregular that I have to do a definitive test of every point against all the vertices of every poly.

Please post your code as it may really give me some great ideas.

--

when small people start casting long shadows, it is time to go to bed


Comment on Re^2: Speeding up point-in-polygon -- take two (Under 40 seconds!)
Re^3: Speeding up point-in-polygon -- take two (Under 40 seconds!)
by BrowserUk (Pope) on Aug 28, 2006 at 17:48 UTC
    Ya but, are your polys regular?

    Using my method, this doesn't affect the performance.

    What does affect it is the size of the coordinate space and the minimum granularity of points.

    Update: I guess someone doesn't believe me ;)


    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      > Update: I guess someone doesn't believe me ;)
      
      Only in a "Wow, that is unbelievable" kinda way. ;-).

      Knowing your experience, I am sure you have some seriously innovative mojo going on there. Please post your code. If I can use it, it will be a great help. Eventually I would release my set of scripts (which do much more than just point-in-polys) as an addition to the general set of Geo:: modules on CPAN.

      Many thanks,

      --

      when small people start casting long shadows, it is time to go to bed

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