[GRASS-user] help needed with v.to.rast

GRASS GRASS user
1

Hi,

I need some help as the results that I get at the moment are not what I expect.

Task:
I want to transfer some irregular spaced points (height values) to a regular spaced dataset by interpolation.

What I tried:
v.in.ascii to import the points (looks good from display)
v.to.rast
r.resamp.interp to interpolate the gaps

The result:
there is still "white" space between the points, depending on the region setting I got some colored spots.

My dataset:
24 z-Values for a region of 195 x 85 m (I know that are not that many points). The z values vary between 368 and 453.

Any ideas/suggestions what I could do to get the desired output?

Regards
Wolfgang

2

Hi,

v.in.ascii to import the points (looks good from display)
v.to.rast
r.resamp.interp to interpolate the gaps

Maybe your approach is correct, but I've never used this command for
interpolation.

If you wish, try this:

v.in.ascii (same as before)

g.region -p -a vect=name_of_your_vector_points_map res=5 (you can
change the value of res, but first try this value, it seems
appropriate to a region of 195x85 meters)

v.surf.rst input=name_of_your_vector_points_map layer=0
elev=name_of_interpolated_raster_map

I hope that will be useful for you, and I hope that my English is not
been so bad.
José María
Saludos

2008/9/13 WolfgangZ <wollez@gmx.net>:

Hi,

I need some help as the results that I get at the moment are not what I
expect.

Task:
I want to transfer some irregular spaced points (height values) to a regular
spaced dataset by interpolation.

What I tried:
v.in.ascii to import the points (looks good from display)
v.to.rast
r.resamp.interp to interpolate the gaps

The result:
there is still "white" space between the points, depending on the region
setting I got some colored spots.

My dataset:
24 z-Values for a region of 195 x 85 m (I know that are not that many
points). The z values vary between 368 and 453.

Any ideas/suggestions what I could do to get the desired output?

Regards
Wolfgang

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

3

José María Michia schrieb:

Hi,

v.in.ascii to import the points (looks good from display)
v.to.rast
r.resamp.interp to interpolate the gaps

Maybe your approach is correct, but I've never used this command for
interpolation.

If you wish, try this:

v.in.ascii (same as before)

g.region -p -a vect=name_of_your_vector_points_map res=5 (you can
change the value of res, but first try this value, it seems
appropriate to a region of 195x85 meters)

v.surf.rst input=name_of_your_vector_points_map layer=0
elev=name_of_interpolated_raster_map

I hope that will be useful for you, and I hope that my English is not
been so bad.
José María
Saludos

Hi José María,

thank you very much, this does what I want! Sometimes it is hard to find the right command within the "hundreds" possible ones.

Any you don't have to worry about your English! Mine is also not perfect as I'm not a native speaker.

Kind regards
Wolfgang

PS: Just installed the native WinGrass 6.3.0-4 today on my new laptop. Worked like a charm. Many thanks also to the creators of the installer!