# octopus-graph tikz/pgfplots

EDIT:I found a solution. See below.

i'm trying to get something like this:

I have small dots and big dots, and some small dots are connected to one big dot. I can "plot" all points with pgfplots:

\addplot[scatter,
only marks,
point meta=explicit symbolic,
scatter/classes={
a={mark=square*,blue},%
b={mark=triangle*,red},%
d={mark=triangle*,green},%
c={mark=o,draw=black}}]
table[x=xs, y=ys, meta=qs] {test.txt};
\end{axis}


But i can't figure out, how to add the connection between single dots.

I'm looking for something like this:

\foreach \x1/\y1/\x2/\y2 in data{
\draw (\x1,\y1) -- (\x2,\y2);
}


Or is there a better way? Btw: All data are generated by myself, therefore it is no problem to change the format.

EDIT: A MWE

\documentclass{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}[]
only marks,
point meta=explicit symbolic,
scatter/classes={
a={mark=square*,blue},%
b={mark=triangle*,red},%
d={mark=triangle*,green},%
c={mark=o,draw=black}}]
table[x=xs, y=ys, meta=qs] {testoutput.txt};
\end{axis}
%or here?
\end{tikzpicture}
\end{document}


with testoutput.txt

xs xs ys qs
155 725 d
195 1215 c
1095 825 c
245 2665 b
395 2850 d
1670 2875 t
15 2660 t
270 1960 t
1715 3010 t
1085 1110 t
1040 685 t
1985 1535 t
580 170 t
2250 2025 t
1815 2925 t
1420 3370 t
160 1125 t
25 500 t
460 640 t
100 70 t
375 170 t
1185 360 t


And then there is an other file connection.dat

155 725 1670 2875
155 725 270 1960
155 725 100 70
155 725 1185 360
1095 825 715 2660
1095 825 1715 3010
1095 825 580 170


It is not sure, which connections i have to made, not until the data is generated.

EDIT2:

     \DTLloaddb[noheader=false]{conns}{connections.dat}
\DTLforeach*{conns}{\xA=x, \yA=y, \xB=a, \yB=b}{%
color=gray]
coordinates {
(\xA,\yA )(\xB,\yB)
};  }


But now i have a little perfomance problem. My datas are big: around 1000 dots and ~500 connections per graph! And i need to plot 8 of them. The time to compile my tex is more than 1.5 minutes! Is there a way to "precompile" the graphs?

• Can you add a sample of the generated data and a full MWE? You can do exactly what you want, excepting of course the need to use \x, \y, \a, and \b (say) because you can't have digits in csnames :) – Sean Allred Sep 16 '14 at 22:34
• I think my only problem is to read correctly from my connection.dat file. – ChuckZee Sep 17 '14 at 7:27
• How do you decide which connections to be drawn or to which point? – percusse Sep 17 '14 at 10:11
• This is quite complex. Let say, it's random. Btw: i found a solution. – ChuckZee Sep 17 '14 at 11:23
• @ChuckZee Don't be this guy: xkcd.com/979; post your solution as an answer :) – Sean Allred Sep 17 '14 at 11:55

You can plot the connections.dat file using the scatter plot style and a couple of visualization depends on statements:

\documentclass{standalone}
\usepackage{pgfplots}
\begin{filecontents}{testoutput.txt}
xs ys qs
155 725 d
195 1215 c
1095 825 c
245 2665 b
395 2850 d
1670 2875 t
15 2660 t
270 1960 t
1715 3010 t
1085 1110 t
1040 685 t
1985 1535 t
580 170 t
2250 2025 t
1815 2925 t
1420 3370 t
160 1125 t
25 500 t
460 640 t
100 70 t
375 170 t
1185 360 t
\end{filecontents}

\begin{filecontents}{connections.dat}
155 725 1670 2875
155 725 270 1960
155 725 100 70
155 725 1185 360
1095 825 15 2660
1095 825 1715 3010
1095 825 580 170
\end{filecontents}

\begin{document}
\begin{tikzpicture}
\begin{axis}[]
only marks,
point meta=explicit symbolic,
scatter/classes={
a={mark=square*,blue},%
b={mark=triangle*,red},%
d={mark=triangle*,green},%
c={mark=o,draw=black}}]
table[x=xs, y=ys, meta=qs] {testoutput.txt};
scatter, only marks, mark=none,
visualization depends on=\thisrowno{0}\as\startx,
visualization depends on=\thisrowno{1}\as\starty,
visualization depends on=\thisrowno{2}\as\endx,
visualization depends on=\thisrowno{3}\as\endy,
scatter/@pre marker code/.code={
\draw (0,0) -- (axis direction cs:{\endx-\startx},{\endy-\starty});
},
scatter/@post marker code/.code={},
] table {connections.dat};
\end{axis}
\end{tikzpicture}
\end{document}

• Thanks. I found a solution by myself. I will try yours as soon as possible. – ChuckZee Sep 17 '14 at 11:27
• @ChuckZee: I don't think it's a good idea to accept this answer if you haven't even tried it out. Could you please post your own solution as an answer and accept that? – Jake Sep 17 '14 at 13:00

My solution with the package datatool

\documentclass{standalone}
\usepackage{pgfplots}
\usepackage{datatool}
\begin{document}
\begin{tikzpicture}
\begin{axis}[]
only marks,
point meta=explicit symbolic,
scatter/classes={
a={mark=square*,blue},%
b={mark=triangle*,red},%
d={mark=triangle*,green},%
c={mark=o,draw=black}}]
table[x=xs, y=ys, meta=qs] {testoutput.txt};

\DTLforeach*{conns}{\xA=x, \yA=y, \xB=a, \yB=b}{%

• Instead of using one \addplot command per connecting line, I would recommend using \draw [gray] (axis cs:\xA,\yA) -- (axis cs:\xB,yB);. That is much more efficient than sending every line through the whole plot processing mechanism. – Jake Sep 17 '14 at 13:22
• @percusse: I think ChuckZee is assuming a connections.dat file like the one in his question, where each line contains two coordinates (xA, yA, xB, yB), and the first coordinate would be the common points (in the example that would be (155,725) and (1095,825)) – Jake Sep 17 '14 at 14:11