[GRASS-user] count vector points (quadrat count)

GRASS GRASS user
1

Dear,

How can I count vector points by region resolution (quadrat count) and write the results in a raster map (in order to perform r.mapcalc on these observed frequencies).

Is v.to.rast the command I should use (v.to.rast input=myvec output=myras use=??? value=???)

Robbie

2

Hi,

You could try r.in.xyz using 'method=n' which will count points per cell
(resolution chosen in g.region) and write a raster map allocating the number
count to the cell.

John

On Thursday 08 April 2010 07:39:12 Robbie Heremans wrote:

Dear,

How can I count vector points by region resolution (quadrat count) and
write the results in a raster map (in order to perform r.mapcalc on these
observed frequencies).

Is v.to.rast the command I should use (v.to.rast input=myvec output=myras
use=??? value=???)

Robbie

3

Thanks John.

v.out.ascii input=myvec format=point | r.in.xyz input=- output=myras method=n type=FCELL x=1 y=2 z=3

does the job.

Robbie

2010/4/8 John Tate <john.tate@ntlworld.com>

Hi,

You could try r.in.xyz using ‘method=n’ which will count points per cell
(resolution chosen in g.region) and write a raster map allocating the number
count to the cell.

John

On Thursday 08 April 2010 07:39:12 Robbie Heremans wrote:

Dear,

How can I count vector points by region resolution (quadrat count) and
write the results in a raster map (in order to perform r.mapcalc on these
observed frequencies).

Is v.to.rast the command I should use (v.to.rast input=myvec output=myras
use=??? value=???)

Robbie

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

4

On Thu, Apr 8, 2010 at 10:55 AM, Robbie Heremans
<robbie.heremans@gmail.com> wrote:

Thanks John.
v.out.ascii input=myvec format=point | r.in.xyz input=- output=myras
method=n type=FCELL x=1 y=2 z=3
does the job.

Excellent.

Now a FAQ:
http://grass.osgeo.org/wiki/Count_points_in_raster_cells

Markus