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

Helena Mitasova hmitaso at unity.ncsu.edu
Tue Feb 17 12:12:07 EST 2009

On Feb 17, 2009, at 11:28 AM, Wolf Bergenheim wrote:

> 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 would strongly suggest to integrate at least the most important  
info into
the man page. Nobody maintains tutorials and other extra docs and  
they become
quickly obsolete. Also many people use man pages so there is a better
change of fixing / enhancing explanations if necessary,

>> 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:>
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