[GRASS-user] Subtracting One Vector Map From Another

GRASS GRASS user
1

   Somehow, my streets map also contains lines for streams. I would like to
subtract the stream lines from the street lines but do not see a module to
do this. Map algebra works well with raster maps (r.mapcalc), but what
module will allow me to do this with two vector maps?

Rich

2

On Mon, Jan 16, 2012 at 10:37 PM, Rich Shepard <rshepard@appl-ecosys.com> wrote:

Somehow, my streets map also contains lines for streams. I would like to
subtract the stream lines from the street lines but do not see a module to
do this. Map algebra works well with raster maps (r.mapcalc), but what
module will allow me to do this with two vector maps?

Vectors are not my thing, but I checked the GRASS Book… maybe v.select?

v.select - Selects features from vector map (A) by features from other vector map (B).

Best,
Marcello.

3

On Mon, 16 Jan 2012, Marcello Gorini wrote:

Vectors are not my thing, but I checked the GRASS Book... maybe v.select?

Marcello,

   I considered useing v.select but after reading the man page I wasn't sure
it would do just what I wanted. Instead, I used the GUI in digitize mode to
remove the street lines that overlay streams.

Thanks,

Rich

4

On Tue, January 17, 2012 01:37, Rich Shepard wrote:

   Somehow, my streets map also contains lines for streams. I would like
to
subtract the stream lines from the street lines but do not see a module to
do this. Map algebra works well with raster maps (r.mapcalc), but what
module will allow me to do this with two vector maps?

For the record: wouldn't v.overlay with operator=not be what you need ?

Moritz