I have a ListPointPlot3D containing four series of data. I would like to be able to define the size, shape and colour of these series individually. Changing the size and colour is crucial, the shape not so much.
The Mathematica documentation is unhelpful for the 3D case, but for 2D plots I managed to get things to work perfectly.
Can anyone advise how best to do this in 3D?,
Thanks
Make up some data:
Table[data[k] =
Table[3 k + Sin[j^2 + i], {i, -Pi, Pi, 0.2}, {j, -2, 2, 0.2}], {k, 4}];
Apply different styles via PlotStyle and Directive to different data sets:
ListPointPlot3D[{data[1], data[2], data[3], data[4]},
PlotStyle -> {
Directive[Opacity[.5], Red, PointSize[.005]],
Directive[Opacity[.5], Blue, PointSize[.01]],
Directive[Opacity[.5], Green, PointSize[.015]],
Directive[Opacity[.5], Black, PointSize[.02]]
}, BoxRatios -> 1]
Related
When exporting rather complicated plots (especially ListDensityPlot) as a PDF or EPS (for publication, for example), the resulting file size can be quite large. For example:
data = Flatten[Table[{f0, f, Exp[-(f - f0)^2/25^2]}, {f0, 500, 700, 5}, {f, 300,
900}], 1];
plot=ListDensityPlot[data,PlotRange->{Automatic,Automatic,{0,1}},InterpolationOrder->0]
This example data set is on the order of the size I typically work with. When I export using Export["C:\\test.pdf", plot], it generates a PDF file 23.9MB in size. If I instead try Export["C:\\test1.pdf", Rasterize[plot]] it is far smaller, but the integrity and rescalability of the image naturally suffers.
This is complicated further if my actual figure is a combined plot, such as (Edit: f goes to 900)
plot2 = Show[plot, Plot[x, {x, 500, 900}, PlotStyle -> Thick]]
(or with some usage of Epilog) where I'd love to have the background ListDensityPlot be rasterized, but keep the other markup and plots in ``vector'' form. Or at the very least, the frame labels be non-rasterized.
Is there any way to do this?
Or, to accomplish the same goal via some other clever method?
Update
I've checked out the related question, but that's gotta be way more complicated than it needs to be (essentially exporting then importing). I've been able to utilize some of the tricks in that question to extract the plot separately from the axes:
axes = Graphics[{}, Options[plot2]]
plots = Graphics[plot2[[1]]]
But, the plots term loses the AspectRatio and PlotRange, etc. plots can be hit with a Rasterize, but it needs dimensional fixing.
And then, how to combine them together?
This is exactly the kind of problem for which I wrote the function linked here:
http://pages.uoregon.edu/noeckel/computernotes/Mathematica/listContourDensityPlot.html
It's based on the same idea as in Heike's answer -- I just added some more features so that you can safely change the aspect ratio, opacity, and combine with other plots. See my comment in Heike's answer.
To try it with your data, do something like this:
plot = Show[
listContourDensityPlot[data,
PlotRange -> {Automatic, Automatic, {0, 1}},
InterpolationOrder -> 0, Contours -> None],
Graphics[Line[{{500, 500}, {700, 700}}]]]
There are a couple of similar functions linked from the parent page, too.
If you're dealing with 2D plots, you could combine a rasterized plot with vectorized axes by using Inset. For example
plot2 = ListDensityPlot[data,
PlotRange -> {Automatic, Automatic, {0, 1}},
InterpolationOrder -> 0, Axes -> False, Frame -> False,
PlotRangePadding -> 0];
plotRange = PlotRange /. AbsoluteOptions[plot2, PlotRange];
plot = Graphics[{
Inset[Image[plot2], plotRange[[All, 1]], {Left, Bottom}, Scaled[{.96, .96}]],
Line[{{500, 500}, {700, 700}}]},
Frame -> True, AspectRatio -> 1,
PlotRange -> plotRange, PlotRangePadding -> Scaled[.02]]
Export["test.pdf", plot]
produces a .pdf of about 400 KB. The frame, tick marks, and black line are still vectorized, so they stay sharp when zooming in:
If you are exporting as PDF, EPs or WMF, then the text should remain as vectors even if you have a rasterized component to the graphics.
I think the trick is to set the number of plot points to some low number in the ListDensityPlot command and then export as PDF as normal.
How about just plotting the function rather than making a list?
plot=DensityPlot[Exp[-(f - f0)^2/25^2], {f0, 500, 700}, {f, 300, 900},
Epilog -> {Thick, Line[{{500, 500}, {700, 700}}]}, PlotPoints -> 50]
Export["test.pdf", plot]
file size 1.1MB
I have a Graphics3D object. I want to export it as a bitmap, and to calculate the bitmap-pixel coordinates of certain 3D points.
Mathematica obviously does a projection from 3D objects to 2D pixel coordinates when it draws the 3D graphic. How can I find out what this projection is?
I'd rather avoid doing lots of tricky geometrical calculations based on ViewVector and ViewAngle and ImageSize and BoundingBox. Is there a shortcut?
Damon.
You could GeometricTransform using the option "Transformation" -> "Perspective". Suppose your projected chess board looks something like this
img = Image#
Plot3D[0, {x, -1, 1}, {y, -1, 1}, Mesh -> 7,
MeshShading -> {{Black, White}, {White, Black}}, Boxed -> False,
AxesEdge -> {{-1, -1}, {-1, -1}, None}, AxesOrigin -> {-1, -1, 0}]
To find the projection you will need the coordinates of at least 4 control points in img for which you know the {x,y}-coordinates. There probably are methods to have Mathematica find these coordinates automatically but you can select them manually by right-clicking on img and choosing "Get Coordinates". Click on the control points of your choice (in this case I chose the 4 corners of the chessboard) and
copy/paste their coordinates to a new line. You should get something like
controls = {{13.5`, 151.5`}, {235.5`, 68.5`},
{332.5`, 206.5`}, {139.5`, 262.5`}};
The projection function and matrix then become
transform = FindGeometricTransform[controls,
{{0, 0}, {8, 0}, {8, 8}, {0, 8}},
"Transformation" -> "Perspective"][[2]]
transfMat = TranformationMatrix[transform]
Note that I chose the chessboard to be an 8x8 square centred at {4,4}, but you can choose any square.
A point {x,y} on the chessboard will now correspond to the point in img with pixel coordinates transform[{x,y}] or, using the projection matrix, (transfMat[[{1,2}]].{x,y,1})/(transfMat[[3]].{x,y,1}). So for example, to put a marker on D6, which would be at position {x,y}={4-1/2,6-1/2} in my 8x8 square, you could do something like
ImageCompose[img, Image[BoxMatrix[2]], Round[transform[{4 - 1/2, 6 - 1/2}]]]
When you render your Graphics3D object, you can specify the ViewMatrix option. You can set the transformation (such as a rotation) and then the projection.
This way you can use your explicit knowledge of the projection used to calculate the correct planar coordinates.
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}]] &)]
I am trying to plot multiple lists in the same plot in Mathematica (ListLinePlot) and use PlotMarkers and the PlotLegend Package to get the final figure. The issue is that Mathematica puts a marker for every point and this makes it hard to tell which marker is where in the plot. Is it possible to have a plot marker appear every n sample (e.g. every 10 points for a 100 point plot).
The Directive at the moment is PlotMarkers->{Automatic, Small}.
I think adding something like Mesh->10 should work for you:
data = Accumulate /# RandomReal[{-1/2, 1}, {3, 100}];
ListLinePlot[data, PlotMarkers -> {Automatic, Small}, Mesh -> 10]
If you want more control over the location of the plot markers than Brett's answer gives you, then you probably have to place the markers manually. Eg (modifying Brett's example)
data = Accumulate /# RandomReal[{-1/2, 1}, {3, 100}];
col = {Red, Blue, Green};
decimate[i_] := {col[[i]], PointSize -> Medium,
Point /# Transpose[{Range[1, 100, 10], data[[i, 1 ;; -1 ;; 10]]}]}
ListLinePlot[data, PlotStyle -> col, Epilog -> Table[decimate[i], {i, 3}]]
Of course Point can be replaced with any graphics object you want - eg Text, Inset etc...
Also remember you can use Tooltip to cause the marker coordinates to pop up when you pass the mouse pointer over it:
The example of what I was describing in the comment. The markers don't behave properly.
Apparently I cannot post images yet, but running the following code
data = Accumulate /# RandomReal[{-1/2, 1}, {3, 100}];
ListLinePlot[data, PlotMarkers -> {Automatic, Small}, Mesh -> 5]
should give improper results. Also the number of data and plots in the same figure is quite large to individually select which points and I would like to keep the same Directives for different plots and data ranges as they tend to vary between 100 to around 300 in each case and I have to save them in different tables as they are used in other calculations along the way.
Plot Posted by belisarius, running the code above
How do you plot legends for functions without using the PlotLegends package?
I, too, was disappointed by the difficulty of getting PlotLegend to work correctly. I wrote my own brief function to make my own custom figure legends:
makePlotLegend[names_, markers_, origin_, markerSize_, fontSize_, font_] :=
Join ## Table[{
Text[
Style[names[[i]], FontSize -> fontSize, font],
Offset[
{1.5*markerSize, -(i - 0.5) * Max[markerSize,fontSize] * 1.25},
Scaled[origin]
],
{-1, 0}
],
Inset[
Show[markers[[i]], ImageSize -> markerSize],
Offset[
{0.5*markerSize, -(i - 0.5) * Max[markerSize,fontSize] * 1.25},
Scaled[origin]
],
{0, 0},
Background -> Directive[Opacity[0], White]
]
},
{i, 1, Length[names]}
];
It is flexible, but not so easy to use. "names" is a list of strings to render in the legend; "markers" is a list with the same length as "names" of Graphics objects representing the plot markers or graphics to render; "origin" is a two-element list with the absolute horizontal and vertical position of the upper-left corner of the legend; "markerSize" is the number of points to scale the markers to; "fontSize" is the font size; "font" is the name of the font to use. Here is an example:
Plot[{x, x^2}, {x, 0, 2}, PlotStyle -> {Blue, Red},
Epilog -> makePlotLegend[
{x, x^2},
(Graphics[{#, Line[{{-1, 0}, {1, 0}}]}]) & /# {Blue, Red},
{0.9, 0.3},
12,
12,
"Arial"
]
]
I would also be very interested in an answer to this question.
To tell you what is wrong with PlotLegends: It is terribly unstable and in many instances doesn't work at all.
Here is an example where PlotLegends screws up completely. Output is from Mathematica 7.0:
Assume that we have measured some data points corresponding to a number of functions, and we want to show how well they compare to the ideal function, or maybe how well they match with a calculated fit. No problem! We'll just Show[] the smooth plot together with a ListPlot of the data points, right?
It could look something like this:
Show[
Plot[{Sin[x], Sinh[x]}, {x, -Pi, Pi}],
ListPlot[Join[{#, Sin[#]} & /# Range[-Pi, Pi, .5],
{#, Sinh[#]} & /# Range[-Pi, Pi, .5]]]
]
Now we'd like to put a legend on the plot, so readers will know what on earth they're looking at. Easier said than done, mister! Let's add the PlotLegend to the Plot[]:
Show[
Plot[{Sin[x], Sinh[x]}, {x, -Pi, Pi}, PlotLegend -> {Sin[x], Sinh[x]}],
ListPlot[Join[{#, Sin[#]} & /# Range[-Pi, Pi, .5],
{#, Sinh[#]} & /# Range[-Pi, Pi, .5]]]
]
This looks GREAT! Publish immediately!
For such a basic and ubiquitously needed functionality, it sure has been a lot of work to find an alternative to PlotLegend that just works. The best alternative I've found so far has been to meticulously construct a list of plotstyles, then construct the legend by hand, and finally to show it together with the plot using ShowLegend[]. (See for example here) It's possible, but a lot of work.
So if anyone knows of a workaround to make PlotLegend work, an alternative package that works better, or just a neat way to get legends that can be automated easily, I would be very grateful! It would certainly make life a little bit easier.
If you are experiencing the weird behavior described by James When you are trying to use 'Show' to combine two images, then you should play around with using the 'Overlay' function instead of 'Show'.
Alternatively, I have found that as long as both graphics have a legend then 'Show' will render the composite image correctly.
If it looks a bit silly having two legends then you can remove the one from the second graphic by using options like:
PlotLegend -> {},
LegendPosition -> {0.1, 0.1},
LegendSize -> 0.001,
LegendShadow -> None,
LegendBorder -> None
This creates an empty and invisible legend but still allows the two graphics to be composed correctly by 'Show'.