[GRASS-dev] proper v.parallel behavior on strange input

[Marco Alicera]

Hi,

IMHO, the wolf`s approach is the good one, since  the 'proper'
parallel line must be choosen by users.

i prefere it because it is flexible and can be very fast if there is
no need to remove the loop or no loop are expected.

marco

2008/5/26, Росен Матев <r.matev at gmail.com>:
> Hi Wolf,
>
>  The thing that bothers me is the upper line segment of the loop. It's
>  parallel to the corresponding segment of input line but it's direction
>  is the opposite. That is quite "non-algorithmic".
>  By the way, I'm pretty sure that I figured out an algorithm, which
>  will create 'proper' parallel line  s (without loops as in Wolf's
>  non-dashed example). Unlike the old method of creating parallel lines
>  with loops and then cleaning the mess, my algorithm works in one
>  piece. (I think the old method doesn't work because you cannot remove
>  the loops properly by only using the line-with-loops itself)
>
>  Rosen
>
>
>  On Mon, May 26, 2008 at 9:15 PM, Wolf Bergenheim
>  <wolf+grass at bergenheim.net> wrote:
>  > Hi!
>  >
>  > IMHO it should loop back, and by default the loop should be detected and
>  > removed. An option to not remove the loop could be cool.
>  >
>  > See attached image. The part that should be removed is drawn with a dashed
>  > line.
>  >
>  > --Wolf
>  >
>  > On 26.05.2008 15:02, Росен Матев wrote:
>  >>
>  >> Hello,
>  >> I'm currently reimplementing v.parallel/v.buffer. There are some
>  >> strange inputs with no apparent behavior. Please suggest what should
>  >> v.parallel do on such inputs.
>  >> I've attached a simple input. Try to make a parallel line on right
>  >> side of the given line; distance is greater than 5m (let's say 7m).
>  >>
>  >>
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>  >>
>  >>
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>  > --
>  >
>  > <:3 )---- Wolf Bergenheim ----( 8:>
>  >
>  >
>
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