[R] can we visualize water flows with 3d in R?
tea3rd at gmail.com
Thu Oct 13 14:35:34 CEST 2016
Very respectfully, there are no R packages that can do what Marna desires.
His/Her data, undoubtably, comes from a 1-D hydraulic model simulation --
where output is generated at channel cross-sections -- representing the
sloping water surface elevation of the centerline of flow in a stream or
river. With mapping software for such problems, the assumption is made that
the water surface intersects the topography (within or beyond the stream
channel) perpendicular to the direction of flow. Hydrodynamically, this is
generally not correct, but it's a reasonable approximation. To do this,
typically, the topography -- in the from of a raster digital elevation
model (DEM) -- is converted to a triangular irregular network (TIN) to
facilitate the creation of a smoother line of intersection between the
water surface and topography. Because, the water surface slopes in a
downstream direction, contour lines are crossed. Hydraulic modeling
software usually is accompanied by this mapping capability, such as with
HEC-RAS with RAS-Mapper, developed by the US Army Corps of Engineers, or
with HEC-GeoRAS, which requires ESRI ARC GIS; but, there is also a QGIS
plugin module that can do this, I believe. These software packages do
facilitate representing the flow in 3D.
On Wed, Oct 12, 2016 at 6:12 PM, David Winsemius <dwinsemius at comcast.net>
> > On Oct 12, 2016, at 4:28 AM, Duncan Murdoch <murdoch.duncan at gmail.com>
> > On 12/10/2016 4:49 AM, Marna Wagley wrote:
> >> Hi R Users,
> >> Is it possible to visualize river flow in 3D (latitude, longitude with
> >> respect to depth)?
> >> The example of my data looks like. Any suggestions?
> >>> dat1
> >> long lat depth flow
> >> 1 1015.9 857 1.00 1.50
> >> 2 1015.9 857 1.25 1.23
> >> 3 1015.9 857 0.50 2.00
> >> 4 1015.9 858 0.10 1.95
> >> 5 1015.9 858 0.20 1.50
> >> 6 1025.0 858 0.30 1.20
> >> 7 1025.0 858 0.40 0.50
> >> 8 1025.0 858 0.35 0.70
> >> 9 1025.0 858 0.24 1.20
> >> Thanks for your help.
> > It may be, but it's hard to give a nice looking graphic of that small
> dataset. You could try the rgl package and use plot3d to show spheres with
> radius depending on the flow rate, for example
> > plot3d(cbind(long, lat, depth), type="s", col="blue", radius=flow/5)
> A complementary option is to install the plot3D package which I see also
> has a plot3Drgl "co-package". The advantage to this option is the
> association with beautiful modeling packages that Karline Soetaert, Peter
> M. J. Herman, and Thomas Petzoldt have been offering to ecologists for the
> last decade. (Packages: deSolve, marelac, seacarb, AquaEnv) A lot of her
> work has been on flows within systems.
> I usually think of "flows" in rivers as being vector fields in an
> incompressible fluid (water) with 6 components per point, but you can also
> think of them as being scalar state variables. So I suppose you could be
> modeling something other than mass flows. (See Package::ReacTran for the R
> portal to that mathematical world.)
> David Winsemius
> > Duncan Murdoch
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> > PLEASE do read the posting guide http://www.R-project.org/
> > and provide commented, minimal, self-contained, reproducible code.
> David Winsemius
> Alameda, CA, USA
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> PLEASE do read the posting guide http://www.R-project.org/
> and provide commented, minimal, self-contained, reproducible code.
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