[GRASSLIST:5839] vector point cropping

GRASS GRASS user
1

Hi,

I have a points-vector & I want to cut out all points that fall within a
polygon.

In GRASS 5.4 you could use s.mask to do this.

In GRASS 5.7, v.select looks like it would work if there was a
"operator=not" option or if v.overlay worked for points.

Any ideas?

Hamish

2

Dear All,
GRASS60, I tried cropping
area vector with points but failed.
in GRASS5.7 it was OK.
Pl act and solve this.
Ravi

--- Hamish <hamish_nospam@yahoo.com> wrote:

Hi,

I have a points-vector & I want to cut out all
points that fall within a
polygon.

In GRASS 5.4 you could use s.mask to do this.

In GRASS 5.7, v.select looks like it would work if
there was a
"operator=not" option or if v.overlay worked for
points.

Any ideas?

Hamish

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3

GRASS60, I tried cropping
area vector with points but failed.
in GRASS5.7 it was OK.

more details are needed. Exact commands? Exact output? Can you reproduce
it with the spearfish57 data set?

> I have a points-vector & I want to cut out all
> points that fall within a polygon.
>
> In GRASS 5.4 you could use s.mask to do this.
>
>
> In GRASS 5.7, v.select looks like it would work if
> there was a "operator=not" option [for v.select] or if v.overlay
> worked for points.
>
> Any ideas?
>
> Hamish

Solution:

[v.hull +] v.in.region + 'v.overlay operator=not' to make a negative
mask of a the polygon, and then 'v.select op=overlap' to only keep the
points in the negative-mask.

Hamish

4

Thanks for the solution.
I will try..
But in GRASS60
Iam unable to
cut a area vector with a points vector
to result in only vectors that contain points.
I find that the result area has vector even not
including any points.
IS THERE A SNAP LIMIT OR WHAT??
Ravi

--- Hamish <hamish_nospam@yahoo.com> wrote:

> GRASS60, I tried cropping
> area vector with points but failed.
> in GRASS5.7 it was OK.

more details are needed. Exact commands? Exact
output? Can you reproduce
it with the spearfish57 data set?

> > I have a points-vector & I want to cut out all
> > points that fall within a polygon.
> >
> > In GRASS 5.4 you could use s.mask to do this.
> >
> >
> > In GRASS 5.7, v.select looks like it would work
if
> > there was a "operator=not" option [for v.select]
or if v.overlay
> > worked for points.
> >
> > Any ideas?
> >
> > Hamish

Solution:

[v.hull +] v.in.region + 'v.overlay operator=not' to
make a negative
mask of a the polygon, and then 'v.select
op=overlap' to only keep the
points in the negative-mask.

Hamish

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