Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
> It would be interesting to have an example dataset to compare the performance of any forthcoming pure-perl solution with what postgres indexing can do. Or graphic libraries (like you mentioned earlier).

I'm trying not to cross that road. ;)

If you want you can compare it against a trivial bounding-box approach of spatial indexing.

You add 4 indexed columns for each polygon and use the formula from my first post to eliminate candidates°.

A simplistic pure Perl solution would probably imply sorted arrays, slices and hash intersections for the AND clause.

(Doesn't scale well but can handle 10000 polygons easily)

You already created your test sample, I doubt the OP ever will.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

°) Nota bene: this doesn't calculate overlaps, it's just a poor man's spatial index to eliminate impossible combinations.


In reply to Re^6: searching polygons not merged by LanX
in thread searching polygons not merged by dideod.yang

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others meditating upon the Monastery: (3)
    As of 2020-08-12 03:59 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?
      Which rocket would you take to Mars?










      Results (64 votes). Check out past polls.

      Notices?