[GRASS-user] r3.in.xyz

[Francois Chartier]

Is it possible to define a horizontal constraints so that more weight is
given on the interpolation of the property horizontally rather than
vertically.
Similarly in kriging we can define a semi variogram with an orientation in
2d, and i would like to know if it can be done in 3d.
Also what about the question regarding the elevations between the top and
bottom of the soil formation.  Is there a possibilty for v vol rst to
consider data points in between top and bottom.

On Jun 28, 2018 03:40, "Moritz Lennert" <mlennert at club.worldonline.be>
wrote:

On 27/06/18 16:32, Francois Chartier wrote:
> So therefore, my approach of generating a soil property at each
> elevation and interpolating is a correct approach.
> Is there a way that i can constrain the interpolation horizontally.

Not sure what you mean by constraining the interpolation horizontally.

You can create a 2D elevation map by interpolating all your height
information of layer 1 (for example using v.surf.rst). Then you create a
second elevation map interpolating the layer 2 height information, etc.

Moritz



> I.
> Cant remember the module name i am using but i am generating the 3d
> raster from the 3d data points directly.
>
>
> On Tue, Jun 26, 2018, 23:38 Moritz Lennert,
> <mlennert at club.worldonline.be <mailto:mlennert at club.worldonline.be>>
wrote:
>
>     On 27/06/18 03:59, Francois Chartier wrote:
>      > Hi,
>      >
>      > I am working with a data set that consists of borehole logs with
>     a Top
>      > of a layer (layer 1) and the top of the underlying layer (layer 2)
>      > (which is also the bottom of the overlying layer 1).  Everything in
>      > between the elevation of top of layer 1 and top of layer 2
>     correspond to
>      > a Layer 1 property.
>      >
>      > The thickness of Layer 1 varies and this layer may not exist
>     everywhere
>      > (pinches out).  Above the Layer the property is different; in other
>      > words the property only starts below the Top of layer 1 until the
>      > underlying Top of the next layer.
>      > Not sure of the capabilities of the interpolation in Grass and
>     working
>      > with a very large data set (i cannot link every top of layers
>     together),
>      > my first approach was to create a each Layer property for every
>      > elevation slice along each Borehole axis, interpolating soil
>     properties
>      > at every elevation between Boreholes.
>      >
>      > I read on another forum that r3.in.xyz <http://r3.in.xyz>
>     <http://r3.in.xyz> can
>      > interpolate in 3D without a Property at every elevation slice,
>      >
>      >   * while respecting the condition that above the Top of the layer
2,
>      >     the property corresponds to the Overlying top layer 1, and
>      >   * that the property is continuous until the next underlying
>     layer 3 -
>      >     can someone confirm this?
>      >
>      > To provide a bit of background, borehole data bases, identify the
>     top of
>      > layer as encountered when drilling downwards, and provide the
>     elevation
>      > of the next layer (pick); in between the soil property is the same,
>      > however there is no data points.  When interpolating, while there
>     is no
>      > data point in between the two geological picks, the property should
>      > still have weight in the interpolation process.
>      >
>
>     I don't think r3.in.xyz <http://r3.in.xyz> is what you need. This

>     module aggregates 3D
>     point data into voxels.
>
>     You probably want to use something like r.to.rast3. This would mean
>     interpolating each layer separately into 2D elevation maps and then
>     assemble them into 3D using r.to.rast3.
>
>     Moritz
>
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