[GRASS5] v.to.sites question

[Markus Neteler]

On Mon, Nov 19, 2001 at 11:30:12AM -0500, Helena Mitasova wrote:
> Markus Neteler wrote:
> 
> > Hi,
> >
> > today I tried to generate a sites file from a vector map
> > (containing a circle). However, the result was not what
> > I expect from the man page:
> >
> >   "If -a flag is selected,
> >    v.to.sites  extracts all vertices from a vector file, if not selected,
> >    it  extracts  site (point) features only, ignoring lines and areas. If
> >    -i  flag  is selected then, for each line, if the distance between any
> >    two  vertices on this line is greater that dmax, additional points are
> >    added to keep the distance withing dmax range."
> >
> > I thought that lots of sites are generated along the vector lines (that's
> > what I need). Am I wrong in my assumption? Is it a bug or a feature...?
> 
> Markus, check your parameters, if you selected -i a spline function is
> used to generate additional points along your line, I haven't used it for a
> while,
> but it used to work (often I forgot to change dmax and it was generating
> lots of points along contours causing problems with segmentation in
> s.surf.rst for reasons
> which are beyond this answer to explain, so now I make sure that my dmax is
> really
> large so that v.to.sites does not add any addtional sites to my data). Also
> make sure that
> you use -c if necessary. So unless somebody has changed it, it should work
> and I suggest that you check your parameters and your data (make sure that
> dmax is smaller
> than the distances between your data points if you want additional data)

Thanks for the hints, but I am not successfull...

GRASS:~ > v.to.sites -ai in=bug out=ring dmax=0.1
 
   v.to.sites:
Number of nodes = 1
GRASS:~ > v.to.sites -aic in=bug out=ring dmax=0.1
 
   v.to.sites:
Number of nodes = 1

Too many bugs around!

Ciao

 Markus