[GRASS-user] Interpolation method for parallel samples

[Markus Neteler]

On Fri, Dec 12, 2014 at 1:43 PM, Martin Album Ytre-Eide
<Martin.Album.Ytre-Eide at nrpa.no> wrote:
> Hello!
>
> I have airborne gamma measurements obtain in lines. The spatial distance
> between the 'points' along the line is 50m (e-w direction) and the spatial
> distance between the lines is 1000m (n-s direction)
>
> I am currently experimenting with the v.surf.bspline function - setting
> ew_step=100 and ns_step=1000. I am having trouble setting the ew_step any
> lower.....? I am also using the smoothing parameter lambda_i.
>
> If anyone have some interpolation tips with this type of data - I would be
> happy to hear about it.

While I am not familiar with this kind of data I wonder if anisotrophy
is involved.
If yes, then you may also check

http://grass.osgeo.org/grass70/manuals/v.surf.rst.html
with
 theta=float    Anisotropy angle (in degrees counterclockwise from East)
 scalex=float  Anisotropy scaling factor

Markus