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

[Росен Матев]

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:>
>
>