[GRASS-dev] Re: [GRASS-user] v.generalize for area boundaries?

[Wolf Bergenheim]

On 17.02.2009 08:35, Hamish wrote:
> Hi, 
> 
> I am following the v.generalize tutorial at
>   http://users.ox.ac.uk/~orie1848/tutorial.html
>    (we should move that to the wiki before it disappears)
> but it doesn't say much about working with areas beyond removing small
> ones.

That page and the images exists in the svn too. How does one go about
adding extra manual pages? Or perhaps we could integrate it into the
manual page itself?

> 
> I have a vector area which has a very "steppy" boundary, like from
> r.to.vect with a sawtooth pattern at the cell edges. I want to run a
> smoothing filter over it to get rid of the jaggy bits.
> 
> No matter what method I try my output map is always the same as the input
> map, no vertices are created or destroyed.
> 
> any ideas how to do this?  I know about 'v.clean tool=prune' and Markus
> Metz's topology-preserving v.simplify (psst- add it to wiki addons) but
> I'd like to learn more about how to use v.generalize.

How large is the cell you exported from? First you have to use a
smoothing operator. When you are done with the smoothing you should use
the douglas method to reduce the number of points.

I'll see if I can whip up an example for you.

--Wolf

-- 

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