Mathematica ListcontourPlot3D - wolfram-mathematica

I have data in the form { {x,y,z,f}...} I am using ListContourPlot3D but all I get is an empty box with dimensions -1 to 1 in each direction. Here is my code:
ListContourPlot3D[data5, PlotRange -> All,
AxesLabel -> {"[Beta]", "[Omega]", "Vo"}, Contours -> {1500}].
These are the first 5 points of my data:( the whole set has 55 points)
{{200, 20000 10^(1/3), 2000, 1226},
{200, 20000 10^(1/3), 2600, 1422},
{200, 20000 10^(1/3), 3200, 1581},
{200, 20000 10^(1/3), 3800, 1761},
{200, 20000 10^(1/3), 4400, 1872}}
Dimensions[data5] returns {55,4}
If I do IntegerPart[data5] it does it correctly so it must recognize the numbers in my data.
I appreciate any ideas.
Thank you.

It's hard to tell without having the entire dataset, but I am betting there is a problem with your Contours -> {1500} setting. What happens if you omit it altogether or use a different value?

Contours -> num
Plots num equally spaced levels contours.
Contours -> {num}
Plots the f[x,y,z] = num contour.
Did you mean the former? I doubt ListContourPlot3D can plot your data if it is too sparse or to localized. For the data sample you gave us x and y do not vary at all. Does x and y vary enough in you final data set to well populate coordinate space?

#Davorak's suggestion that the data set, as written, does not seem to vary may be the cause of the problem. Assuming that is not the case, try rotating the resulting graphic, and if you see a black plane appear, then it is the color scheme that is off. By default, ListContourPlot3D produces an opaque white surface, and I've had issues where it did not seem to produce anything, but it was just invisible. The solution: add a ContourStyle option, and set it to something like Red.

The problem is using the {x,y,z,f} form of ListContourPlot3D at low resolution.
I stumbled over this a few weeks ago as well, here is a minimal example of the bug:
xyzfdata[r_] := Flatten[#, 2] &#Table[{x, y, z, x^2 + y^2 + z^2 - 1},
{x, -2, 2, r}, {y, -2, 2, r}, {z, -2, 2, r}];
(* Low resolution {x,y,z,f} fails *)
ListContourPlot3D[xyzfdata[1], Contours -> {0}]
The solution in my case (I had my data on a grid) was to use the grid form and DataRange:
fdata[r_] := Table[x^2 + y^2 + z^2 - 1,
{z, -2, 2, r}, {y, -2, 2, r}, {x, -2, 2, r}];
(* Low resolution works ok for array data *)
ListContourPlot3D[fdata[1], Contours -> {0},
DataRange -> 2 {{-1, 1}, {-1, 1}, {-1, 1}}]
I think the issue is that for the {x,y,z,f} form, the implementation uses interpolation in a way that fails at low resolution. Upping the resolution in the first example, everything works:
(* Higher resolution {x,y,z,f} works *)
ListContourPlot3D[xyzfdata[.2], Contours -> {0}]

Related

Mathematica: Extract Co-ordinates of a Plot for which I do not know the Equation of

GIven a 2D plot in Mathematica, if you keep clicking the graph, a sequence of co-ordinates of that graph are shown. I'd like to extract the x and y co-ordinates of ALL of these points, WITHOUT using the "Get Coordinates" tool (which only extracts one co-ordinate at a time, which is both inaccurate and laborious). An additional constraint is that the equation of the plot is UNKNOWN (I found a graph produced by Wolfram Alpha, the equation of which is unknown to me. If I can simply extract the co-ordinates, I can fit a spline through those co-ordinates, thereby getting the equation of the graph). Any ideas?
Cheers!
This is how it can be done in Mathematica 9.
First obtain the chart.
chart = WolframAlpha["density vs altitude of heterosphere",
{{"EntrainedDensityPlot:AtmosphericLayers", 1}, "Content"}]
Extract the data section. The x-axis is scaled according to the tick specification.
data = chart[[1, 1, 1, 1, 1, 1, 3, 2, 1]];
ListLinePlot[data, PlotRange -> All]
This is the content of the tick specification :-
ticksposition = Position[chart, Ticks];
ticks = Last#chart[[Sequence ## Most[First#ticksposition]]];
Take[First#ticks, 5][[All, 1]]
{-25.328436022934504, -18.420680743952367, -11.512925464970229`,
-4.605170185988091, 2.302585092994046}
The numbers above relate to the following tick labels :-
{10^-11, 10^-8, 10^-5, 0.01, 10};
The line data is show below. The x values can be rescaled according to the ticks.
data
{{7.56584506772668,-5.},{7.522454313212941,-4.5},{7.4785653196771396,-4.},{7.4342573821331355,-3.5},{7.38950218524746,-3.},{7.344266755495627,-2.5},{7.2985804103507865,-2.},{7.25233739856673,-1.5},{7.205635176410364,-1.},{7.158436173289435,-0.5},{7.110696122978827,0.},{7.062448668658617,0.5},{7.0136456542395695,1.},{6.964230125910116,1.5},{6.91433359434226,2.},{6.863751143484082,2.5},{6.812620083867098,3.},{6.760878083121377,3.5},{6.708511342992233,4.},{6.655491829094075,4.5},{6.601814187258075,5.},{6.547459502017843,5.5},{6.4924064877997925,6.},{6.436647039879506,6.5},{6.380156434630315,7.},{6.32290629486736,7.5},{6.264901893476659,8.},{6.206091938653852,8.5},{6.1464577290734805,9.},{6.086001700931971,9.5},{6.0246816979681785,10.},{5.962473333757384,10.5},{5.899349258200177,11.},{5.821358081393286,11.5},{5.7428108616236795,12.},{5.664279054878501,12.5},{5.585749407744609,13.},{5.507199708509977,13.5},{5.42873140526997,14.},{5.350245459408396,14.5},{5.2717680313145,15.},{5.114815113005919,16.},{4.957937505095806,17.},{4.801148069229532,18.},{4.6443908991413725,19.},{4.487624622133048,20.},{4.326976291408619,21.},{4.16682025054415,22.},{4.007442270191581,23.},{3.848827581930999,24.},{3.6909772521960824,25.},{3.533890923387621,26.},{3.3775192543075785,27.},{3.221911213411722,28.},{3.0670291554360247,29.},{2.9128939952449864,30.},{2.7595034826911258,31.},{2.606755482950629,32.},{2.4486747988659405,33.},{2.2912612192626023,34.},{2.1357509841344284,35.},{1.9820905307957144,36.},{1.680194560884901,38.},{1.3852187828929574,40.},{1.096877451374393,42.},{0.8148779691310925,44.},{0.5389464994826453,46.},{0.27512860638016096,48.},{0.02654455522211221,50.},{-0.21614311166946532,52.},{-0.44783517527478434,54.},{-0.6842865521277486,56.},{-0.9256594818782552,58.},{-1.1722157727127442,60.},{-1.8127175638195325,65.},{-2.490977037365282,70.},{-3.220852777752422,75.},{-3.992257398138752,80.},{-4.801233732898559,85.},{-4.884341907755072,85.5},{-4.967863202252387,86.},{-5.6792850030558135,90.},{-6.576295584184468,95.},{-7.486859743501422,100.},{-9.239975177105872,110.},{-10.71451777375279,120.},{-11.71724726204385,130.},{-12.472384692245763,140.},{-13.085067592660632,150.},{-13.606060333782066,160.},{-14.062050687084879,170.},{-14.470591537717763,180.},{-14.842453559942024,190.},{-15.185537946620293,200.},{-15.50507451487766,210.},{-15.805477093216508,220.},{-16.359148622816097,240.},{-16.864221756309153,260.},{-17.331782147471895,280.},{-17.7704410644037,300.},{-18.1863994482277,320.},{-18.582846794542757,340.},{-18.964546221796557,360.},{-19.333726745661632,380.},{-19.69257556476376,400.},{-20.554367300484596,450.},{-21.37431184148772,500.},{-22.157071180737354,550.},{-22.89745771517206,600.},{-23.585866797897218,650.},{-24.206758461335397,700.},{-24.74733834618318,750.},{-25.200922702635545,800.},{-25.573825183196032,850.},{-25.880257267404012,900.},{-26.137443089588984,950.},{-26.360979711632908,1000.}}
Recycling an answer from here, this function stores up mouse point clicks in a variable pts. You will need to combine your curve in the Show function, suitably scaled. Here I just put in a sine plot.
It uses a dynamic module so the points will still be there when you save, close and reopen your notebook.
CreateDistribution[] :=
DynamicModule[{savepts = {{-1, -1}}},
Dynamic[EventHandler[
Show[Plot[Sin[x], {x, 0, 7}],
ListPlot[pts, AxesOrigin -> {0, 0},
PlotRange -> {{0, 7}, {0, 5}}]],
"MouseDown" :> (savepts =
pts = DeleteCases[
Append[pts, MousePosition["Graphics"]], {-1, -1}])],
Initialization :> (pts = savepts)]]
CreateDistribution[]
pts
{{0.371185, 0.357737}, {0.859027, 0.779375}, {1.55898,
1.01471}, {2.36498, 0.661709}, {2.95887,
0.161626}, {3.55277, -0.358067}, {4.10424, -0.799316}, {4.91024, -0.985622}, {5.6314, -0.573789}, {6.20409, -0.142345}, {6.71314,
0.367543}}

How to export ContourPlot3D surface and regenerate it in Excel, Originlab or some other similar softwares

I tried this, but failed.
fig3D = ContourPlot3D[ x^2 + y^3 - z^2 == 0, {x, -2, 2}, {y, -2, 2}, {z, -2, 2},
PlotPoints -> 100]
pts = (InputForm#fig3D)[[1, 1, 1]];
ListSurfacePlot3D[pts]
The regenerated surface is very poor. Any suggestions? thanks!
Not too bad if you specify MaxPlotPoints
ListSurfacePlot3D[pts, Mesh -> None, MaxPlotPoints -> 100]
Compare with
ListSurfacePlot3D[pts]
Edit
Regarding the export to Excel, please consider that the Excel surface plot is a very basic construction and requires a matrix whose first file and column are the XY values with the Z values in the inner cells. Example:
So, exporting a working dataset to Excel may require (an unspecified amount of) data massaging.

Dynamic (or forced) scaling of ColorFunction

Reading this question on importing ColorData from matlab, I was wondering if there is a way to change the range of values over which the ColorFunction is scaled. That was probably not entirely clear, so let me show with a figure from matlab (the same example as in the previous question is used)
The plot on the left is the original, with the ColorData mapped to the data values between -1 and 1. Now, I can easily set it to be mapped to the data values between 0 and 1, the result being that all values less than 0 are assigned blue color (lowest in the colormap). PlotRange is the closest function, and using ClippingStyle in addition to that produces a similar figure. However, it doesn't re-scale the ColorData to map to the plot range.
How can I do this in Mathematica?
BTW, to insert colorbars using Mathematica, you can look at this function
Here's a function applied to a surface:
Plot3D[x + y, {x, -2, 2}, {y, -2, 2},
ColorFunction -> (ColorData["Rainbow", #3] &), Mesh -> {{1}, {1}}]
To look at the top-right corner, with the same color function and scaling, I set ColorFunctionScaling -> False, and manually scale the color function to map the (global) minimum to zero and the maximum to one using Rescale:
Plot3D[x + y, {x, 1, 2}, {y, 1, 2}, ColorFunctionScaling -> False,
ColorFunction -> (ColorData["Rainbow", Rescale[#3, {-4, 4}, {0, 1}]] &)]

Mathematica: How to obtain data points plotted by plot command?

When plotting a function using Plot, I would like to obtain the set of data points plotted by the Plot command.
For instance, how can I obtain the list of points {t,f} Plot uses in the following simple example?
f = Sin[t]
Plot[f, {t, 0, 10}]
I tried using a method of appending values to a list, shown on page 4 of Numerical1.ps (Numerical Computation in Mathematica) by Jerry B. Keiper, http://library.wolfram.com/infocenter/Conferences/4687/ as follows:
f = Sin[t]
flist={}
Plot[f, {t, 0, 10}, AppendTo[flist,{t,f[t]}]]
but generate error messages no matter what I try.
Any suggestions would be greatly appreciated.
f = Sin[t];
plot = Plot[f, {t, 0, 10}]
One way to extract points is as follows:
points = Cases[
Cases[InputForm[plot], Line[___],
Infinity], {_?NumericQ, _?NumericQ}, Infinity];
ListPlot to 'take a look'
ListPlot[points]
giving the following:
EDIT
Brett Champion has pointed out that InputForm is superfluous.
ListPlot#Cases[
Cases[plot, Line[___], Infinity], {_?NumericQ, _?NumericQ},
Infinity]
will work.
It is also possible to paste in the plot graphic, and this is sometimes useful. If,say, I create a ListPlot of external data and then mislay the data file (so that I only have access to the generated graphic), I may regenerate the data by selecting the graphic cell bracket,copy and paste:
ListPlot#Transpose[{Range[10], 4 Range[10]}]
points = Cases[
Cases[** Paste_Grphic _Here **, Point[___],
Infinity], {_?NumericQ, _?NumericQ}, Infinity]
Edit 2.
I should also have cross-referenced and acknowledged this very nice answer by Yaroslav Bulatov.
Edit 3
Brett Champion has not only pointed out that FullForm is superfluous, but that in cases where a GraphicsComplex is generated, applying Normal will convert the complex into primitives. This can be very useful.
For example:
lp = ListPlot[Transpose[{Range[10], Range[10]}],
Filling -> Bottom]; Cases[
Cases[Normal#lp, Point[___],
Infinity], {_?NumericQ, _?NumericQ}, Infinity]
gives (correctly)
{{1., 1.}, {2., 2.}, {3., 3.}, {4., 4.}, {5., 5.}, {6., 6.}, {7.,
7.}, {8., 8.}, {9., 9.}, {10., 10.}}
Thanks to Brett Champion.
Finally, a neater way of using the general approach given in this answer, which I found here
The OP problem, in terms of a ListPlot, may be obtained as follows:
ListPlot#Cases[g, x_Line :> First#x, Infinity]
Edit 4
Even simpler
ListPlot#Cases[plot, Line[{x__}] -> x, Infinity]
or
ListPlot#Cases[** Paste_Grphic _Here **, Line[{x__}] -> x, Infinity]
or
ListPlot#plot[[1, 1, 3, 2, 1]]
This evaluates to True
plot[[1, 1, 3, 2, 1]] == Cases[plot, Line[{x__}] -> x, Infinity]
One way is to use EvaluationMonitor option with Reap and Sow, for example
In[4]:=
(points = Reap[Plot[Sin[x],{x,0,4Pi},EvaluationMonitor:>Sow[{x,Sin[x]}]]][[2,1]])//Short
Out[4]//Short= {{2.56457*10^-7,2.56457*10^-7},<<699>>,{12.5621,-<<21>>}}
In addition to the methods mentioned in Leonid's answer and my follow-up comment, to track plotting progress of slow functions in real time to see what's happening you could do the following (using the example of this recent question):
(* CPU intensive function *)
LogNormalStableCDF[{alpha_, beta_, gamma_, sigma_, delta_}, x_] :=
Block[{u},
NExpectation[
CDF[StableDistribution[alpha, beta, gamma, sigma], (x - delta)/u],
u \[Distributed] LogNormalDistribution[Log[gamma], sigma]]]
(* real time tracking of plot process *)
res = {};
ListLinePlot[res // Sort, Mesh -> All] // Dynamic
Plot[(AppendTo[res, {x, #}]; #) &#
LogNormalStableCDF[{1.5, 1, 1, 0.5, 1}, x], {x, -4, 6},
PlotRange -> All, PlotPoints -> 10, MaxRecursion -> 4]
etc.
Here is a very efficient way to get all the data points:
{plot, {points}} = Reap # Plot[Last#Sow#{x, Sin[x]}, {x, 0, 4 Pi}]
Based on the answer of Sjoerd C. de Vries, I've now written the following code which automates a plot preview (tested on Mathematica 8):
pairs[x_, y_List]:={x, #}& /# y
pairs[x_, y_]:={x, y}
condtranspose[x:{{_List ..}..}]:=Transpose # x
condtranspose[x_]:=x
Protect[SaveData]
MonitorPlot[f_, range_, options: OptionsPattern[]]:=
Module[{data={}, plot},
Module[{tmp=#},
If[FilterRules[{options},SaveData]!={},
ReleaseHold[Hold[SaveData=condtranspose[data]]/.FilterRules[{options},SaveData]];tmp]]&#
Monitor[Plot[(data=Union[data, {pairs[range[[1]], #]}]; #)& # f, range,
Evaluate[FilterRules[{options}, Options[Plot]]]],
plot=ListLinePlot[condtranspose[data], Mesh->All,
FilterRules[{options}, Options[ListLinePlot]]];
Show[plot, Module[{yrange=Options[plot, PlotRange][[1,2,2]]},
Graphics[Line[{{range[[1]], yrange[[1]]}, {range[[1]], yrange[[2]]}}]]]]]]
SetAttributes[MonitorPlot, HoldAll]
In addition to showing the progress of the plot, it also marks the x position where it currently calculates.
The main problem is that for multiple plots, Mathematica applies the same plot style for all curves in the final plot (interestingly, it doesn't on the temporary plots).
To get the data produced into the variable dest, use the option SaveData:>dest
Just another way, possibly implementation dependent:
ListPlot#Flatten[
Plot[Tan#t, {t, 0, 10}] /. Graphics[{{___, {_, y__}}}, ___] -> {y} /. Line -> List
, 2]
Just look into structure of plot (for different type of plots there would be a little bit different structure) and use something like that:
plt = Plot[Sin[x], {x, 0, 1}];
lstpoint = plt[[1, 1, 3, 2, 1]];

how to animate 3d plot given a rotation axis in mathematics

If given a rotation axis normalized, such as {1/Sqrt[3],1/Sqrt[3],1/Sqrt[3]}, and a 3d plot, for example,
z[x_, y_] := Exp[-(Sqrt[x^2 + y^2]/Power[4, (3)^-1]) +
Power[4, (3)^-1]*Sqrt[1/2*(Sqrt[x^2 + y^2] + x)]];
Plot3D[2*z[x, y], {x, -5, 5}, {y, -5, 5}]
I want to create an animation for this plot about the axis {1/Sqrt[3],1/Sqrt[3],1/Sqrt[3]} (could be any other arbitary one), and then export it as an animated gif. Would anyone please help? Many thanks.
Edit
I also left out one degree of freedom in specifying the rotation. Could any one please help, if also given the coordinate of a point which the rotational axis must pass, how to do the visualization/animation?
Thanks again.
Copying what Daniel did, just prepared for exporting.
axis = {1, 1, 1};
l = {-7, 7};
s = Table[
Plot3D[2*z[x, y], {x, -5, 5}, {y, -5, 5}, PlotRange -> {l, l, l}] /.
gg : GraphicsComplex[___] :> Rotate[gg, theta, axis], {theta, 0., 2. Pi}];
Export["c:\\test.gif", s]
The following parameters are available for the gif export (as per the docs):
"AnimationRepetitions" how many times the animation is played before stopping
"Background" background color shown in transparent image regions
"BitDepth" bits used to represent each color channel in the file
"ColorMap" color reduction palette, given as a list of color values
"GlobalColorMap" default color palette for individual animation frames
"DisplayDurations" display durations of animation frames, given in seconds
"ImageCount" number of frames in an animated GIF
"ImageSize" overall image size
"RawData" array of color map indices
"Comments" user comments stored in the file
I used "DisplayDurations" in the past, and it worked.
Could do as below.
axis = {1, 1, 1};
Animate[
Plot3D[2*z[x, y], {x, -5, 5}, {y, -5, 5}] /.
gg : GraphicsComplex[___] :> Rotate[gg, theta, axis],
{theta, 0., 2.*Pi}]
Daniel Lichtblau
Wolfram Research

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