Group Abstract

Message Boards

WOLFRAM COMMUNITY

3.2K Views

4 Replies

0 Total Likes

View groups...

Follow this post

Share this post:

GROUPS:

Graphics and Visualization Wolfram Language

How to place equally spaced PlotMarkers in a plot?

KRISHAN SHARMA

Posted 3 years ago

Hello, I want the Markers to be eaually spaced. Here is my code ClearAll["Global`"]; \[Sigma] = 20; Kn = {0, 0.025, 0.05, 0.1}; Subscript[\[Sigma], v] = 0.85; Subscript[\[Alpha], v] = (2 - Subscript[\[Sigma], v])/ Subscript[\[Sigma], v]; \[Alpha] = Subscript[\[Alpha], v] Kn; u = (\[Sigma] (BesselI[0, \[Sigma]] - BesselI[0, r \[Sigma]] + \[Alpha] \[Sigma] BesselI[ 1, \[Sigma]]))/(\[Sigma] BesselI[ 0, \[Sigma]] + (-2 + \[Alpha] \[Sigma]^2) BesselI[1, \[Sigma]]); u1[r_] := (BesselI[0, \[Sigma]] - BesselI[0, r \[Sigma]])/ BesselI[2, \[Sigma]]; data = Table[{r, u1[r]}, {r, 0, 1, 0.01}]; Vslip = Plot[ u, {r, 0, 1}, PlotRange -> {{0, Automatic}, {0, Automatic}}, AxesOrigin -> {0, 0}, LabelStyle -> {FontFamily -> "Times New Roman", 24, Bold}, PlotLegends -> Placed[{Style["\!\(\ StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0", {Bold, 20}], Style["\!\(\* StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.025", 20], Style["\!\(\* StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.05", 20], Style["\!\(\* StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.1", 20]}, {Left, Bottom}], PlotStyle -> {{Black, Thick}, {Blue, Thick}, {Red, Thick}, {Green, Thick}, {Orange, Thick}} ]; Vnoslip = ListPlot[data, PlotMarkers -> {"\[EmptySquare]", 24}, AxesOrigin -> {0, 0}, PlotRange -> {{0, Automatic}, {0, Automatic}}, LabelStyle -> {FontFamily -> "Times New Roman", 24, Bold}, PlotLegends -> {Placed[{Style["\!\(\* StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0 (Sharma et al.[])", \ {Bold, 20}]}, {Left, Bottom}], Placed[Style[Framed["\!\(\* StyleBox[\"\[Sigma]\",\nFontSlant->\"Italic\"]\)=1", RoundingRadius -> 5], {Bold, 20}], {Center, Bottom}]}, PlotStyle -> {Black, Thick} ]; Show[Vnoslip, Vslip, ImageSize -> Large, AxesStyle -> {Black, Black}, AxesLabel -> {r, "\!\(\*OverscriptBox[\(u\), \(^\)]\)"}, PlotLabel -> Style["(a)", 24, Black] ] Plot markers are unequally space as depicted in fig above.

Hello, I want the Markers to be eaually spaced. Here is my code

ClearAll["Global`*"];
\[Sigma] = 20;
Kn = {0, 0.025, 0.05, 0.1};
Subscript[\[Sigma], v] = 0.85;
Subscript[\[Alpha], v] = (2 - Subscript[\[Sigma], v])/
  Subscript[\[Sigma], v];
\[Alpha] = Subscript[\[Alpha], v] Kn;
u = (\[Sigma] (BesselI[0, \[Sigma]] - 
     BesselI[0, 
      r \[Sigma]] + \[Alpha] \[Sigma] BesselI[
       1, \[Sigma]]))/(\[Sigma] BesselI[
     0, \[Sigma]] + (-2 + \[Alpha] \[Sigma]^2) BesselI[1, \[Sigma]]);
u1[r_] := (BesselI[0, \[Sigma]] - BesselI[0, r \[Sigma]])/
  BesselI[2, \[Sigma]];
data = Table[{r, u1[r]}, {r, 0, 1, 0.01}];
Vslip = Plot[
   u, {r, 0, 1},
   PlotRange -> {{0, Automatic}, {0, Automatic}},
   AxesOrigin -> {0, 0},
   LabelStyle -> {FontFamily -> "Times New Roman", 24, Bold},
   PlotLegends -> Placed[{Style["\!\(\*
StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0", {Bold, 20}], 
      Style["\!\(\*
StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.025", 20], Style["\!\(\*
StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.05", 20], Style["\!\(\*
StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0.1", 20]}, {Left, Bottom}],
   PlotStyle -> {{Black, Thick}, {Blue, Thick}, {Red, Thick}, {Green, 
      Thick}, {Orange, Thick}}
   ];
Vnoslip = ListPlot[data,
   PlotMarkers -> {"\[EmptySquare]", 24},
   AxesOrigin -> {0, 0},
   PlotRange -> {{0, Automatic}, {0, Automatic}},
   LabelStyle -> {FontFamily -> "Times New Roman", 24, Bold},
   PlotLegends -> {Placed[{Style["\!\(\*
StyleBox[\"Kn\",\nFontSlant->\"Italic\"]\)=0 (Sharma et al.[])", \
{Bold, 20}]}, {Left, Bottom}], Placed[Style[Framed["\!\(\*
StyleBox[\"\[Sigma]\",\nFontSlant->\"Italic\"]\)=1", 
        RoundingRadius -> 5], {Bold, 20}], {Center, Bottom}]},
   PlotStyle -> {Black, Thick}
   ];
Show[Vnoslip, Vslip,
 ImageSize -> Large,
 AxesStyle -> {Black, Black},
 AxesLabel -> {r, "\!\(\*OverscriptBox[\(u\), \(^\)]\)"},
 PlotLabel -> Style["(a)", 24, Black]
 ]

enter image description here

Plot markers are unequally space as depicted in fig above.

POSTED BY: KRISHAN SHARMA

4 Replies

Sort By:

Michael Rogers

Michael Rogers, Emory University

Posted 3 years ago

I don't know if there's an easy way. I *assume* you want the markers evenly spaced in the scaled coordinate system of the displayed plot. The units in the x and y directions are not equal, so the apparent distance is not the true distance. I'm also assuming the markers are not to mark data but to help identify the curve in the plot. Here are two ways: (1) The mesh function `ArcLength` gives mesh points evenly spaced by arc length. You need to scale the coordinate system to get "evenly spaced" to mean even spaced in screen coordinates. It takes a few steps to calculate the appropriate scaling, including a trial calculation of the plot. The we'll map the `Point` objects generated by `Mesh` to the desired marker. plot = Plot[(BesselI[0, 20] - BesselI[0, 20 r])/BesselI[2, 20], {r, 0, 1}]; aspectRatio = AspectRatio /. AbsoluteOptions[plot, AspectRatio]; scalingfactor = aspectRatio/Ratios[Differences /@ PlotRange[plot]][[1, 1]]; plot = Plot[(BesselI[0, 20] - BesselI[0, 20 r])/BesselI[2, 20], {r, 0, 1}, MeshFunctions -> {ArcLength}, Mesh -> 15, ScalingFunctions -> {scalingfactor # &, #/scalingfactor &}]; Normal@plot /. Point -> (GeometricTransformation[ Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], #] &) You can add markers at the end point by hand with `Show`, if they are desired. A simple way: Graphics[{ GeometricTransformation[ Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], {0., u1[0.]}], GeometricTransformation[ Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], {1., u1[1.]}] }] (2) The function ````will take care of the`PlotRange` part of the scaling above, but you still have to adjust for the aspect ratio: aspectRatio = AspectRatio /. Options[ListLinePlot, AspectRatio]; Show[ListLinePlot[data], Graphics[{ GeometricTransformation[ Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], GraphUtilities`LineScaledCoordinate[ data . DiagonalMatrix[{1, aspectRatio}], #] . DiagonalMatrix[{1, 1/aspectRatio}] & /@ Subdivide[0., 1., 16]] }], AspectRatio -> aspectRatio ]

I don't know if there's an easy way. I assume you want the markers evenly spaced in the scaled coordinate system of the displayed plot. The units in the x and y directions are not equal, so the apparent distance is not the true distance. I'm also assuming the markers are not to mark data but to help identify the curve in the plot.

Here are two ways:

(1) The mesh function ArcLength gives mesh points evenly spaced by arc length. You need to scale the coordinate system to get "evenly spaced" to mean even spaced in screen coordinates. It takes a few steps to calculate the appropriate scaling, including a trial calculation of the plot. The we'll map the Point objects generated by Mesh to the desired marker.

plot = Plot[(BesselI[0, 20] - BesselI[0, 20 r])/BesselI[2, 20], {r, 0, 1}];
aspectRatio = AspectRatio /. AbsoluteOptions[plot, AspectRatio];
scalingfactor = 
  aspectRatio/Ratios[Differences /@ PlotRange[plot]][[1, 1]];
plot = Plot[(BesselI[0, 20] - BesselI[0, 20 r])/BesselI[2, 20], {r, 0, 1},
   MeshFunctions -> {ArcLength}, Mesh -> 15, 
   ScalingFunctions -> {scalingfactor # &, #/scalingfactor &}];
Normal@plot /. 
 Point -> (GeometricTransformation[
     Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], #] &)

You can add markers at the end point by hand with Show, if they are desired. A simple way:

Graphics[{
  GeometricTransformation[
         Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], {0., u1[0.]}],
  GeometricTransformation[
         Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}], {1., u1[1.]}] 
 }]

(2) The function ```will take care of thePlotRange` part of the scaling above, but you still have to adjust for the aspect ratio:

aspectRatio = AspectRatio /. Options[ListLinePlot, AspectRatio];
Show[ListLinePlot[data],
 Graphics[{
   GeometricTransformation[
    Inset[Style["\[EmptySquare]", FontSize -> 24], {0., 0.}],
    GraphUtilities`LineScaledCoordinate[
        data . DiagonalMatrix[{1, aspectRatio}], #] . 
       DiagonalMatrix[{1, 1/aspectRatio}] & /@ Subdivide[0., 1., 16]]
   }],
 AspectRatio -> aspectRatio
 ]

POSTED BY: Michael Rogers

Eric Rimbey

Posted 3 years ago

As far as I can tell from the documentation, you won't be able to do this with PlotMarkers. That option seems specific to the ListPlot family of plotting methods and it always places markers at the values in the data being plotted. An alternative might be to use Plot. You can interpolate your data and use PlotStyle. fn = Interpolation[data]; Plot[fn[x], {x, 0, 1}, PlotStyle -> {Black, Dashed}] Of course, you wanted little squares, not dashing, but I thought this might be acceptable. If not, then I don't know how to use PlotStyle (or some other option) to automatically place markers. You could generate the graphical markers explicitly yourself (maybe using the interpolation to place them evenly) and add them to your Show expression.

POSTED BY: Eric Rimbey

KRISHAN SHARMA

Posted 3 years ago

Thanks, I think using Dot in place of Dashed in PlotStyle can work. Only the size and spacing between the Dots if we able to manage. Is there any way to increases the spacing between the dots?

POSTED BY: KRISHAN SHARMA

KRISHAN SHARMA

Posted 3 years ago

Using AbsoluteDashing in place of Dashed is working.

POSTED BY: KRISHAN SHARMA

Reply to this discussion

Reply Preview

Attachments

Remove Add a file to this post

Follow this discussion

or Discard

Feedback