[GRASS-user] Anisotropy

[Francois Chartier]

thanks, i will try it in a little while and let u know.  if i understand
the principal, then it assumes the point is just further in distance for
the interpolation but keeps the value at its original coordinate.
to give more weight to a horizontal direction, the z scale needs to be
increased vertically and potentially shortened horizonatlly.

On Sat, Mar 16, 2019, 17:47 Benjamin Ducke <benducke at fastmail.fm wrote:

> On 16/03/2019 21:24, Francois Chartier wrote:
> > I thought Zscale was used to convert units ft to m, i didnt know it was
> > for giving more weight to one direction.
>
> That's only one application case. The manual page
> goes on:
>
> 'Rescaling of z-coordinates (zscale) is also needed when the distances
> in vertical direction are much smaller than the horizontal distances ..'
>
> That is equivalent to what you are looking
> for: instead of assuming that a process works
> slower or faster in the Z direction (anisotropy),
> you could also assume the speed is the same but
> the Z distance is shorter/longer, no?
>
> If I understand the manual page correctly, then
> 'zscale' only rescales Z values during
> interpolation, but the original coordinates are
> preserved in the voxel output.
>
> Why not just experiment and check if it produces
> a useful result?
>
> Cheers,
>
> Ben
>
> >
> > Le sam. 16 mars 2019 à 15:20, Benjamin Ducke <benducke at fastmail.fm
> > <mailto:benducke at fastmail.fm>> a écrit :
> >
> >     On 16/03/2019 19:51, Francois Chartier wrote:
> >     > Hi,
> >     >
> >     > Is it possible to add anisotropy when conducting interpolation for
> 3D
> >     > raster.  I would like to give more weight horizontally than
> vertically
> >     > in the 3D interpolation process.
> >
> >     'v.vol.rst' has an option 'zscale'.
> >     Is that not what you are looking for?
> >
> >     Best,
> >
> >     Benjamin
> >
> >     >
> >     > thanks,
> >     >
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> >
> >
> >
> >     --
> >     Dr. Benjamin Ducke
> >     Deutsches Archäologisches Institut (DAI)
> >     Zentrale Berlin, IT-Referat
> >
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> >
>
>
>
> --
> Dr. Benjamin Ducke
> Deutsches Archäologisches Institut (DAI)
> Zentrale Berlin, IT-Referat
>
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