[GRASS-user] Creating vector lines from vector or raster points

GRASS GRASS user
1

I’d like to create vector lines from vector or raster point data. I have rasters of x and y wind components and have used r.mapcalc to compute the x and y values of the original raster grid points and the x and y values for displacements points due to the wind speed and direction. I’d like to take these x and y location values in these rasters and create vector lines that connect the original x,y grid points to the displacement points. I can create vector points with these values at the gird points using r.to.vect, but not sure how to create new vector lines with the info.

Thanks,
Lee

2

Lee Eddington wrote:

I'd like to create vector lines from vector or raster point data. I have
rasters of x and y wind components and have used r.mapcalc to compute the x
and y values of the original raster grid points and the x and y values for
displacements points due to the wind speed and direction. I'd like to take
these x and y location values in these rasters and create vector lines that
connect the original x,y grid points to the displacement points. I can
create vector points with these values at the gird points using r.to.vect,
but not sure how to create new vector lines with the info.

Does the m.cogo module help? See:

http://grass.osgeo.org/grass64/manuals/m.cogo.html OR
http://grass.osgeo.org/grass70/manuals/m.cogo.html

Nikos

3

Lee Eddington wrote:

> I'd like to create vector lines from vector or raster point data. I have
> rasters of x and y wind components and have used r.mapcalc to compute the
> x and y values of the original raster grid points and the x and y values
> for displacements points due to the wind speed and direction. I'd like to
> take these x and y location values in these rasters and create vector
> lines that connect the original x,y grid points to the displacement
> points. I can create vector points with these values at the gird points
> using r.to.vect, but not sure how to create new vector lines with the
> info.

Nikos:

Does the m.cogo module help? See:

http://grass.osgeo.org/grass64/manuals/m.cogo.html OR
http://grass.osgeo.org/grass70/manuals/m.cogo.html

+ something like the following perhaps:

http://casoilresource.lawr.ucdavis.edu/drupal/node/989

N