[Tex/LaTex] Filled contour plot from data set

asymptotecontourgnuplot

I want to create a filled contour plot in pgfplot from a dataset mydata.dat

I get a ugly picture like this:

The code that I use is

\documentclass{standalone}

\usepackage{pgfplots}
\usepgfplotslibrary{colorbrewer,patchplots}
\pgfplotsset{compat=newest}

\pgfplotsset{
colormap={parula}{
rgb255=(53,42,135)
rgb255=(15,92,221)
rgb255=(18,125,216)
rgb255=(7,156,207)
rgb255=(21,177,180)
rgb255=(89,189,140)
rgb255=(165,190,107)
rgb255=(225,185,82)
rgb255=(252,206,46)
rgb255=(249,251,14)}}

\begin{document}
\begin{tikzpicture}
\begin{axis}[
height=9cm,
width=15cm,
view={0}{90},
mesh/ordering=x varies,
mesh/cols=66,
mesh/rows=61,
xtick={1,1.5,2,2.5,3,3.5,4},
colorbar,
ymin=350,
ymax=1000,
point meta min=0.1, 
point meta max=30,
colorbar sampled,
colorbar style={ylabel=$z$},
xlabel=$x$,
ylabel=$y$,
shader=interp]
%\addplot3[surf] table[x=x, y=y, z=z] {mydata.dat};
%\addplot3[contour gnuplot={number = 20,labels={false}}] table[x=x, y=y, z=z] {mydata.dat};
\addplot3[contour filled={number = 20,labels={false}}] table[x=x, y=y, z=z] {mydata.dat};
\end{axis}
\end{tikzpicture}
\end{document}

What I want is a filled contour plot with "hard edges"
This code gives me such nice hard edged but I do not manage to fill the area between the contours.

\addplot3[contour gnuplot={number = 20,labels={false}}] table[x=x, y=y, z=z] {mydata.dat};

example figure using gnuplot

I have found this tread, which shows how to create a filled contour plot of a function using Asimptote. I have a dataset instead of a function and do not know how to use Asimptote with a dataset.

Can anyone help me with implementing this ?

Best Answer

I realise this is an old question, but I just lost a lot of time on the same problem so here I go...

The answer seems lie with your PDF viewer. The pgfplots manual states the following on filled contour plots:

Beware: Viewer Limitations The following paragraph makes uses of pdf features which are unsupported by some free viewers (including pdf.js and evince). Please resort to a suitable viewer if you see unexpected results.

Your dataset is no longer available, so I cannot compile your code to show you what it looks like if you view it in a compatible viewer. I found as the answer to another question here on StackExchange:

\documentclass[tikz,border=3pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
  domain=-2:2,
  view={0}{90},
  colorbar right,
  colorbar style={%
     ytick=data,
  }  
]
\addplot3[contour filled={number=13}]
{exp(-x^2-y^2)*x+0.5};
\end{axis}
\end{tikzpicture}
\end{document}

If I view it with Preview (on Mac) or in Chrome, it looks like this:

If I view it in Adobe Reader, however, it looks like it should:

Related Solutions

Plot Surface from Data – How to Use pgfplots and Asymptote

If you have octave installed, you can triangulate the data from within your LaTeX document using the \addplot shell functionality and plot it using the patch plot style.

\documentclass[border= 5mm]{standalone}
\usepackage{pgfplots}

\begin{document}
    \begin{tikzpicture}
    \begin{axis}
        \addplot3 [patch, patch table={triangles.txt}
   ] shell {echo "data=dlmread('data.txt');
    tri=delaunay(data(:,1), data(:,2));
    dlmwrite('triangles.txt',tri-1,' ');
    disp(data)" | octave --silent};
    \end{axis}
    \end{tikzpicture}
\end{document}

You can also grid the data:

\documentclass[border= 5mm]{standalone}
\usepackage{pgfplots}

\begin{document}
    \begin{tikzpicture}
    \begin{axis}
    \addplot3 [surf, mesh/cols=50, z buffer=sort, restrict z to domain=0:inf, shader=faceted interp] shell {
    echo "
        data=dlmread('data.txt');
        res=\pgfkeysvalueof{/pgfplots/mesh/cols};
        [xx,yy] = meshgrid(linspace(min(data(:,1)), max(data(:,1)),res), linspace(min(data(:,2)), max(data(:,2)),res));
        zz=griddata(data(:,1),data(:,2),data(:,3),xx,yy);
        zz(isnan(zz))=-999;
        disp([xx(:) yy(:) zz(:)])
    " | octave --silent};   
    \addplot3 [only marks] file {data.txt};
    \end{axis}
    \end{tikzpicture}
\end{document}

Gnuplot could be used to interpolate scattered data, but the available interpolation functions don't work particularly well for this dataset.

\documentclass[border= 5mm]{standalone}
\usepackage{pgfplots}

\begin{document}
    \begin{tikzpicture}
    \begin{axis}
    \addplot3 [surf] gnuplot [raw gnuplot] {
        set dgrid3d 30,30 spline;
        splot 'data.txt';       
    };
    \addplot3 [only marks] table {data.txt};
    \end{axis}
    \end{tikzpicture}
\end{document}

PGFPlots Asymptote Gnuplot – How to Fill a Contour Plot

enter image description here

Another possibility: filled contours with Asymptote, MWE:

% fcontour.tex:
\documentclass{article}
\usepackage[inline]{asymptote}
\usepackage{lmodern}
\begin{document}
\begin{figure}
\begin{asy}
import graph;
import contour;
import palette;
defaultpen(fontsize(10pt));
size(14cm,8cm,IgnoreAspect);
pair xyMin=(1,74);  
pair xyMax=(3,86);
real f(real x, real y) {return -2.051^3*1000/(2*3.1415*(2.99*10^2)^2)/(x^2*Cos(y)^2);}
int N=200;
int Levels=16;
defaultpen(1bp);
bounds range=bounds(-3,-0.10); // min(f(x,y)), max(f(x,y))
real[] Cvals=uniform(range.min,range.max,Levels);
guide[][] g=contour(f,xyMin,xyMax,Cvals,N,operator --);
pen[] Palette=Gradient(Levels,rgb(0.3,0.06,0.5),rgb(0.9,0.9,0.85));
for(int i=0;i<g.length-1;++i){
  filldraw(g[i][0]--xyMin--(xyMax.x,xyMin.y)--xyMax--cycle,Palette[i],darkblue+0.2bp);
}
xaxis("$x$",BottomTop,xyMin.x,xyMax.x,darkblue+0.5bp,RightTicks(Step=0.2,step=0.05),above=true);
yaxis("$y$",LeftRight,xyMin.y,xyMax.y,darkblue+0.5bp,LeftTicks(Step=2,step=0.5),above=true);
palette("$f(x,y)$",range,point(SE)+(0.2,0),point(NE)+(0.3,0),Right,Palette,
        PaletteTicks("$%+#0.1f$",N=Levels,olive+0.1bp));
\end{asy}
\caption{A contour plot.}
\end{figure}
\end{document}
% 
% To process it with `latexmk`, create file `latexmkrc`:
% 
%     sub asy {return system("asy '$_[0]'");}
%     add_cus_dep("asy","eps",0,"asy");
%     add_cus_dep("asy","pdf",0,"asy");
%     add_cus_dep("asy","tex",0,"asy");
% 
% and run `latexmk -pdf fcontour.tex`.

Best Answer

Related Solutions

Plot Surface from Data – How to Use pgfplots and Asymptote

PGFPlots Asymptote Gnuplot – How to Fill a Contour Plot

Related Question