[GRASS-dev] Re: [GRASS-user] problem with v.edit tool=merge

[Martin Landa]

Hi,

2007/3/30, Maciej Sieczka <tutey at o2.pl>:
> Martin Landa wrote:
> > Hi,
> >
> > no, there is another problem. Merge tool has been updated and snap
> > tool not. Snap tool in v.edit is very simple:
> >
> > 1) select lines
> > 2) snap *first two* lines from the list [regardless of threshold -- it
> > is a bug]
> >
> > see [1,2]
> >
> > Behaviour of merge tool is a little bit different. It tries to merge
> > *all* selected lines.
> >
> > So there is *important* question for future development of v.edit,
> > should be snap tool updated (snap all selected lines) or merge tool
> > modified according to current simplified snap tool (i.e. merge only
> > first two selected lines and  leave rest of selected lines untouched)?
>
> I'd vote for selective merge and snap tools. One could repeat v.edit in
> a loop in order to merge or snap more than two lines, is that correct?

Yes it would be possible, but a bit time-consuming. Let's say we have
a vector map containing 1e5 lines. We select (by bbox && where) 1e4
lines for merging... Maybe not good example, v.edit is designed as
*low-level* editing tool (do not edit more then *few* features at the
time).

Currently, merge and snap tools have different nature. Let's say we
select three lines from vector map. Snap tool snaps first two line
from selected three lines (maybe should snap lines only when exactly
two lines are selected??) but merge tool tries to merge all three
selected lines. When you select two lines behaviour or merging and
snapping is the same.

1) Snap approach allows user to edit only *two* lines at time.
2) Merge approach allows edit *two and more* lines at time.

I'd vote for 2) but not fully, maybe it does not follow original
v.edit proposal.

Martin

-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *