[GRASS-user] v.generalize: strange behaviour on win?

[Markus Metz]

On Sat, Jan 28, 2012 at 9:12 AM, Paolo Cavallini <cavallini at faunalia.it> wrote:
> Il 27/01/2012 19:24, Markus Metz ha scritto:
>
>> v.generalize is broken in 6.4.1
>
> oh, so it's the different version - I didn't know v.generalize was changed recently,
> thanks for letting me know. strangely enough, in Linux (6.4.1) it works well, whereas
> in Windows (AFAIK 6.4.2RC3) it does not.
> Any explanation?

Yes. The quality of the result is judged by the integrity of the
output data. Therefore the result of 6.4.1 is bad and the result of
6.4.2 is good, contrary to your interpretation. You can try 6.4.1 with
the boundary_county vector in the North Carolina dataset and a
threshold of 100. Half of North Carolina disappears, the areas that
are left have mixed up attributes. That was fixed such that boundaries
are not generalized if the generalization would damage topology. For
your example vector I would recommend a much smaller threshold,
starting with 10, then maybe 20. You could easily end up with a much
higher reduction that with threshold = 100000.

Markus M