[GRASS-user] v.centroids question

[Nikos Alexandris]

On Wed, 2008-03-19 at 12:12 -0700, John C. Tull wrote:
> On Mar 19, 2008, at 11:08 AM, Nikos Alexandris wrote:
> >> John,
> >>
> >> maybe you could try
> >>
> >> v.clean with type=line,boundary,centroid,area tool=snap,break,rmdupl
> >> thresh=.01
> >>
> >> Not sure but I suspect the "break" tool is what you might need.
> >
> > And then of course the rest with v.centroids
> >
> 
> Nikos,
> 
> Thanks for the suggestion. I seem to be getting closer. I ran v.clean  
> as you suggested, then ran v.clean with tool=chdangle and a really big  
> threshold value.
Ah.. ok!


>  Now many more areas are available, but there are  
> still quite a few apparently closed polygons that are not being picked  
> up as areas. I'm playing around with different thresholds for snap and  
> various permutations of the various operations.

So, if I understand, the idea is:

lines to boundaries (v.type) > snap (close open boundaries) + chdangle
(dangles from boundary to line) >  v.centroids

Maybe I misunderstood the "break" tool here. I thought it would help but
maybe it's irrelevant (?)

If it's not too much work could you copy-paste your commands (if
successful)?


Thank you,

Nikos