[GRASS5] Re: New operation to v.select: noverlap

[Radim Blazek]

It sounds good but v.select works for the whole map,
is it your intention to check individual features?
Note this case:
+---+  +---+
| +-+--+-+ |
| | |  | | |
| +-+--+-+ |
+---+  +---+

Radim

On 1/7/06, Wolf Bergenheim <wolf+grass at bergenheim.net> wrote:
> Allan, good news! I just figured out a way to do the contains operator.
> is contained by can be doe by reversing a and b.
>
> Here is what I plan to do, this is a bit technical, but it will serve as
> a project plan (;
>  * Check that every point of B is in A by calling Vect_point_in_area()
>  * If this is true, then check that all points of A are not included in
>         B with the same function. This is to ensure that A does not
>         contain surprises like this:
> +--+  +----+
> |  | *|  A |
> + ++--+--+ |
> | || *|  | |
> | |+--+  | |
> | |     B| |
> | +------+ |
> +----------+
> Here A does not contain B (even if all ponts of B are inside A), because
> of the "bay" marked by *.
>
> Markus, Radim how does this sound?
>
> --Wolf
>
> On 13/12/05 16:24, Wolf Bergenheim wrote:
> > On 13/12/05 16:02, Allan Metts wrote:
> >
> >>At 04:56 PM 12/12/2005, Wolf Bergenheim wrote:
> >>
> >>
> >>
> >>>This patch adds another option to v.select, "noverlap". This is the
> >>>opposite of overlap. So all fetaures not in b are selected from a.
> >>
> >>
> >>Thanks, Wolf...
> >>
> >>I recently had the need for "a contains b" and "a is-contained-by b"
> >>in v.select. Any chance you want to add these as well, since you're on a
> >>roll ? :)
> >>
> >
> >
> > Ahmm.. I'm not sure I would know how to do that. The noverlap was easy,
> > since there was no need to do any checking. All I had to do was reverse
> > the overlap case. But it sounds like an interesing challange. I'll
> > probably do it, but no promises! (;
> >
> > --W
> >
>
> --
>
> <:3 )---- Wolf Bergenheim ----( 8:>
>
>