Geometry Boost List: Re: [geometry] difference algorithm produces invalid polygon?

Subject: Re: [geometry] difference algorithm produces invalid polygon?
From: Barend Gehrels (barend_at_[hidden])
Date: 2012-02-21 13:42:32

Hi Volker,

Thanks for all your reports!

On 21-2-2012 15:38, Volker Schöch wrote:
> Hello again,
> here is another example of (asymmetric) difference producing output that is invalid as input to itself:
>
> (...)
> I am still using boost 1.48.0, my polygon type is oriented counter-clockwise and not closed, my point type is based on int.

I can reproduce this in 1.49 based on int. So alas it is not solved in 
the meantime.

Using double coordinates it is OK and Boost.Geometry's results are 
identical to SQL Server's results (w.r.t. area - there are some "spikey" 
lines which differ).

So it is an int-problem.

I will have a closer look coming weeks - hope to solve this for 1.50.

Regards, Barend