Graphics, Figures & Tables ⇒ Combine pgfplots' axis environment and tikz graphics

[tush]

I want to reproduce the following plot:

graph.png (42.4 KiB) Viewed 4989 times

It is made of the following points (red in image):
\fill[red] (0,{sin(2*pi*1.2*0 r)}) circle (2pt);
\fill[red] (1,{sin(2*pi*1.2*1 r)}) circle (2pt);
\fill[red] (2,{sin(2*pi*1.2*2 r)}) circle (2pt);
% and so on up until the 21st point:
\fill[red] (20,{sin(2*pi*1.2*20 r)}) circle (2pt);
Now I want to add the curve

sine eqt.png (1.57 KiB) Viewed 4989 times

So as I learned from googling it up, the way to that is use pgfplots:
\begin{axis}
[clip=false,xmin=0,xmax=20]
\addplot[samples=500,domain=0:20]{sin(2*pi*1.2*deg(x))};
\end{axis}

But the output I get is this:

Screen Shot 2021-04-10 at 16.36.40.png (121.81 KiB) Viewed 4989 times

What I understand is that pfgplots axis environment and tikz graphics are not sitting on the same place on the canvas.

My question is how to properly reproduce the plot at the top of the thread?

I am not new to LaTeX but I am new to tikz and pgfplots.

Still I couldn't find an answer to this kind of issue. Only answers I found across the web are how to plot a single function.

The full code is given here:

Code: Select all

\documentclass{standalone} 
\usepackage{tikz,pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis} [xmin=0,xmax=20]
\addplot[samples=500,domain=0:20]{sin(2*pi*1.2*deg(x))};
\end{axis}

\draw[help lines] (0,-1) grid (20,1) [step=0.5cm];
% List of points:
\fill[red] (0,{sin(2*pi*1.2*0 r)}) circle (2pt);
\fill[red] (1,{sin(2*pi*1.2*1 r)}) circle (2pt);
\fill[red] (2,{sin(2*pi*1.2*2 r)}) circle (2pt);
\fill[red] (3,{sin(2*pi*1.2*3 r)}) circle (2pt);
\fill[red] (4,{sin(2*pi*1.2*4 r)}) circle (2pt);
\fill[red] (5,{sin(2*pi*1.2*5 r)}) circle (2pt);
\fill[red] (6,{sin(2*pi*1.2*6 r)}) circle (2pt);
\fill[red] (7,{sin(2*pi*1.2*7 r)}) circle (2pt);
\fill[red] (8,{sin(2*pi*1.2*8 r)}) circle (2pt);
\fill[red] (9,{sin(2*pi*1.2*9 r)}) circle (2pt);
\fill[red] (10,{sin(2*pi*1.2*10 r)}) circle (2pt);
\fill[red] (11,{sin(2*pi*1.2*11 r)}) circle (2pt);
\fill[red] (12,{sin(2*pi*1.2*12 r)}) circle (2pt);
\fill[red] (13,{sin(2*pi*1.2*13 r)}) circle (2pt);
\fill[red] (14,{sin(2*pi*1.2*14 r)}) circle (2pt);
\fill[red] (15,{sin(2*pi*1.2*15 r)}) circle (2pt);
\fill[red] (16,{sin(2*pi*1.2*16 r)}) circle (2pt);
\fill[red] (17,{sin(2*pi*1.2*17 r)}) circle (2pt);
\fill[red] (18,{sin(2*pi*1.2*18 r)}) circle (2pt);
\fill[red] (19,{sin(2*pi*1.2*19 r)}) circle (2pt);
\fill[red] (20,{sin(2*pi*1.2*20 r)}) circle (2pt);

\end{tikzpicture}
\end{document}

Any kind of help would be much appreciated.

[Bartman]

The grid and the red dots must be drawn within the axis environment so that the coordinates are correct.

My result-oriented adaptation of the mathematical expression is based on trial and error, it is not a mathematically desirable approach.

Code: Select all

\documentclass{standalone} 
\usepackage{pgfplots}

\pgfplotsset{compat=1.17}

\begin{document}
\begin{tikzpicture}
  \begin{axis}[
    width=12cm,
    height=\pgfkeysvalueof{/pgfplots/width}/2,
    axis x line=center,
    axis y line=left,
    xmax=20.5,
    ymin=-1.2, ymax=1.2,
    xtick={0,5,...,20},
    ytick={-1,0,1},
    clip=false
  ]
  \addplot[samples=500,domain=0:20]{sin(2/5*pi*deg(x))};

  % List of points:
  \pgfplotsinvokeforeach{0,...,20}{
    \fill[red] (#1,{sin(2*pi*1.2*#1 r)}) circle (2pt);
  }
  \end{axis}
\end{tikzpicture}
\end{document}

[tush]

@Bartman Thanks a lot!