[GRASS-dev] Re: r.surf.nnbathy + v.out.ascii?

[Maciej Sieczka]

Hamish,

Thanks for feedback!

Hamish wrote:

> I've added a new -r flag and fs= option to v.out.ascii in CVS which may
> make it more appropriate than having to run v.to.rast first to make a
> raster grid.

But if the input is contour lines? Rasterising it and interpolating the
raster seems the best way to go.

> beware the -r flag (only export within current region) is 3D aware, so
> top and bottom region settings matter.
> 
> I thought I remembered something about the input to nnbathy input
> needing to be sorted by Y value. Is this true? Does it have to be
> gridded or can in be randomly spaced?

It can be randomly spaced as you wish. Natural neighbor interpolation
is an excellent approach for gridding random, clustered input.

> r.surf.nnbaty additions:
> 
> #%option
> #% key: vect
> #% type: string
> #% gisprompt: old,vector,vector
> #% description: The 3D points vector to interpolate

Like I said - this would work only with vector points I guess. Please
correct me if I'm wrong.

Maciek