[GRASS-user] interpolation from massive vector point input

[Micha Silver]

On 27/08/2012 12:58, Johannes Radinger wrote:
> Hi,
>
> I get a text file from a hydromorphological model which includes
> an massive amount of geographical points with attributes (velocity,depth,..),
> which I input using v.in.ascii (around 120000 points).
> The points are located in a river (20 m widht) in a resolution of
> appr. 20x20 cm,
> but this is not fixed and depending on their location within in the river
> (points in the outer bends show rougher resolution then points in the
> inner bends).
> So these points are not regularly (in the sense of raster map) distributed.
>
> Anyway I want to generate a raster surface (resolution = appr. 0.25)
> from the vector points attributes, e.g  a surface of velocity and one
> for depth.
> Additionally to the vector points there is a line vector indicating
> the shore line
> of the river (depth=0 and velocity = 0).
I would use the shoreline to create a polygon of the river area. THen 
convert that polygon to a raster, and use it as a MASK. Once the MASK is 
in place, the interpolation will work only on the area of the river.
And as Madi suggested, try v.surf.rst.

> Now I am looking for a method for interpolation of these points. I
> found v.surf.icw
> which would take into account that there is a shoreline which is not overflown
> by the water (interpolates within the river). But it is not recommended for such
> massive data point input. Is there any other recommendable way fur such
> a purpose (considering the shore line and that there is 0 velocity and
> 0 depth on land?
>
> Any suggestions are welcome!
>
> Thank you,
>
> /johannes
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-- 
Micha Silver
052-3665918