[R-sig-Geo] Semi-join?

[Tim Keitt]

On Tue, May 7, 2019 at 1:39 PM Edzer Pebesma <edzer.pebesma using uni-muenster.de>
wrote:

>
>
> On 5/7/19 8:29 PM, Tim Keitt wrote:
> > I keep finding things that are trivial in sql are not so in R, so perhaps
> > you can help me out.
> >
> > What would be the way in the 'sf' package to retain only polygons from
> one
> > coverage that intersect points in another coverage? I think that's a
> > semi-join.
> >
> > Roughly: 'select a.* from polys a, points b where st_intersects(a.geom,
> > b.geom)'
>
> a[b,]
>
> # or
>
> st_join(a, b, left = FALSE) # no left join gives you inner join
>

Hmm... tried this and for some reasons it was not giving me what I wanted.
I will investigate.

THK


>
> >
> > Thanks.
> >
> > THK
> >
>
> --
> Edzer Pebesma
> Institute for Geoinformatics
> Heisenbergstrasse 2, 48151 Muenster, Germany
> Phone: +49 251 8333081
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo using r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >> This message is from an external sender. Learn more about why this <<
> >> matters at https://links.utexas.edu/rtyclf.                        <<
>


-- 
Timothy H. Keitt
Professor of Integrative Biology and
Associate Chair for Undergraduate Education
http://www.keittlab.org/

	[[alternative HTML version deleted]]