On 13/10/2016 8:35 AM, Thomas Adams wrote:
All,
Very respectfully, there are no R packages that can do what Marna desires.
I would guess that's not literally true, in that there are several
graphics packages that are very flexible. You could well be right that
there are none that are designed specifically for this purpose, so she's
probably going to have to do some work to get what she wants.
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.
Do you know any sample figures online that would show the type of graph
that is usually used here?
Duncan Murdoch
Tom
On Wed, Oct 12, 2016 at 6:12 PM, David Winsemius
<dwinsem...@comcast.net <mailto:dwinsem...@comcast.net>> wrote:
> On Oct 12, 2016, at 4:28 AM, Duncan Murdoch
<murdoch.dun...@gmail.com <mailto:murdoch.dun...@gmail.com>> wrote:
>
> 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.)
Best;
David Winsemius
>
> Duncan Murdoch
>
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David Winsemius
Alameda, CA, USA
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