[GRASS-user] r3.in.xyz

Wed Jul 4 16:40:33 PDT 2018

Any ideas for this question?

On Sun, Jul 1, 2018, 13:27 Francois Chartier, <fra.chartier at gmail.com>
wrote:

> Hi,
>
>
>
> I am reposting the initial question:
>
>
>
> “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.
>
>
> The key question is can v.vol.rst (changed this from r3.in.xyz)
> 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.”
>
>
>
> Thank You
>
>
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *Vaclav Petras <wenzeslaus at gmail.com>
> *Sent: *June 28, 2018 8:27 PM
> *To: *Francois Chartier <fra.chartier at gmail.com>
> *Cc: *Moritz Lennert <mlennert at club.worldonline.be>; GRASS user list
> <grass-user at lists.osgeo.org>
> *Subject: *Re: [GRASS-user] r3.in.xyz
>
>
>
> Hi, I'm not following this discussion fully, but don't you need just
> r.to.rast3elev followed by some raster algebra with ifs (r3.mapcalc)?
>
>
>
> https://grass.osgeo.org/grass74/manuals/r.to.rast3elev.html
>
> https://grass.osgeo.org/grass74/manuals/r3.mapcalc.html
>
>
>
> Best,
>
> Vaclav
>
>
>
> On Thu, Jun 28, 2018 at 12:18 PM, Francois Chartier <
> fra.chartier at gmail.com> wrote:
>
> 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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