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

Wolf Bergenheim wolf+grass at bergenheim.net
Mon May 26 18:24:20 EDT 2008


Hi Rosen,

On 26.05.2008 22:50, Росен Матев wrote:
> 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".

It is a result of the precondition that the parallel line cannot cross 
the line to the left side when following. It is allowed for it to cross 
the original line when going in the opposite direction.

Hope this vague explanation helps.

--Wolf

> 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)

Cool. Looking forward to seeing it :)

--Wolf

-- 

<:3 )---- Wolf Bergenheim ----( 8:>



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