Gnuplot
From Torben's Wiki
Contents |
Basics
Simple Plot
data = 'data.dat' plot data #or plot sin(x)
Plot multiple lines
plot\ "1.dat" title "Eins"\ ,"2.dat" title "Zwei"\ ,"3.dat" title "Drei"\
png output
set terminal png giant size 1024,768 set output "plot.png" plot sin(x) unset output
Multiplot / 2 stacked plots
set multiplot layout 2,1 columnsfirst plot sin(x) plot cos(x) unset multiplot
Plot different columns of same file using 2 y-axes
data = 'data.dat' plot\ data using 1:3 title "Drei" axes x1y2 \ ,data using 1:2 title "Zwei"
Common Mistakes / Errors
Integer division:
use 10.0 / 3 instead of 10/3
Plot Region of Function
plot \ (x<=0.0)||(x>=0.5)?1/0:sin(x) \ , (x<=0.5)||(x>=1.0)?1/0:cos(x)
Layout
Terminals
set terminal postscript enhanced eps color solid # solid!!! set terminal png enhanced giant size 1024,768
For PostScript and MP you should
set border back
as otherwise the frame is drawn twice (can be found using inkscape)
My Favorite: Terminal MP (Metapost) (needs Latex and UbuntuPackage texlive-metapost)
#term = "png"
term = "mp"
if (term eq "png" ) set terminal png enhanced giant size 1024,768
if (term eq "mp" ) set terminal mp color solid latex psnfss prologues 2 magnification 1.00
outfile="plot123"
set output outfile . "." . term
plot sin(x)
unset output
if (term eq "mp" ) \
system ("mpost -tex=latex '".outfile.".mp'")
; system ("mv " . outfile . ".0 " . outfile .".mps") \
; system ("convert -density 300 ".outfile.".mps ".outfile.".png") \
; system ("rm -f ".outfile.".mpx")
; system ("rm -f ".outfile.".log")
; system ("rm -f ".outfile.".mp")
General
set title "Plot Title" # set default plot style set style function points # define linestyles set style line 1 lt 1 lw 2 # Legend position set key top right # or set key off # advanced: set key bottom left box width -3 reverse Left samplen 2 #invert title "Sinus" # default: set key on right top vertical Right noreverse noinvert samplen 4 spacing 1.25 title "" nobox
Axes
set xlabel "Time (s)"
set ylabel "Current (A)"
set grid xtics ytics
# set tics
set xtics mirror
set ytics mirror
# add some tics
set xtics add (0.003, 0.03, 0.3)
set xtics add ("Pi" 3.14159)
# Disable autorange of axes
set xrange [1:*]
set yrange [2.8E-08:3.0E-08]
set logscale y
# set format of number to 1e-03 etc
set format y "%1.e"
# 10^x
set format y "10^{%L}"
# "%" sign:
set format y "%g%%"
# % sign in Terminal MP (Latex)
set format y "%g".'\%%'
# NullAchsen einfügen
set zeroaxis
# or
set xzeroaxis ls -1 lw 2
Linked axes
Linked tics on top axes e.g. bottom=nanometer/top=eV [1]
set x2label "Temp (C)" set x2tics (\ "25" 1000/(c0C+25) \ , "50" 1000/(c0C+50) \ , "75" 1000/(c0C+75) \ , "100" 1000/(c0C+100) \ , "125" 1000/(c0C+125) \ )
Important: you have to set plot range for x and x2!!!
plot [xmin:xmax] [*:*] [xmin:xmax]
Links: [2]
Add Text to Plot
set label "text" at 3.3e-3,90e-3
plot ...
set label 1 sprintf("Ea = %3.5g",-b*ckb/ce) at 3.3e-3,90e-3
plot ...
unset label 1
# position can be given via differnet systems: first (=x axes), second (=x2 axes), graph (=pos in graph area 0.0..1.0) , screen, character
# see help set coordinates
set label "text" at graph 0.25, graph 0.75
Colors
set color of axes label or tics to that of line XYZ
set ylabel "Label" textcolor lt 1 set ytics textcolor lt 1
Draw Line/Arrow
set arrow nohead from 0,0 rto 10,1 set arrow from fitLow, graph 0 to fitLow, graph 1 nohead lc -1 lw 2 plot ... unset arrow
Note: set arrow must be placed before the plot command
Draw circle, rectangle, ellipse, or polygon
set object 1 circle at xwert , ywert behind
Fonts
in Linux run
export GDFONTPATH=/usr/share/fonts/truetype/msttcorefonts
than you can use all the fonts in that dir. For example
set terminal png giant font "Arial,24"
Latex Fonts
From [3], needs Linux package "cm-super")
set term postscript fontfile '/usr/share/texmf/fonts/type1/public/cm-super/sfrm1000.pfb' "SFRM1000"
or after copying the file
set term postscript fontfile '/MessSoftware/sfrm1000.pfb' "SFRM1000"
Greek Symbols in Latex
To get a greek letter, you have to use the postscript terminal, with the option enhanced. Then, to add the alpha greek letter, you have to type {/Symbol a}. Analogously for other letters, changing the "a" by other, like "D" for Delta and so on... [4]
Modify Default Line Types/Styles
set style line 1 lw 2 set style line 2 lw 2 set style line 3 lw 2 set style line 4 lw 2 set style line 5 lw 2 set style line 6 lw 2 set style line 7 lw 2 set style line 8 lw 2 set style line 9 lw 2 set style line 10 lw 2 set style increment user # important!!! switch between linetypes (default) and userdefined linestyles
Fitting
b=5 f(x) = x**b fit f(x) "data.dat" using 1:2 via b plot "data.dat" title "data" notitle, f(x) title "fit" # to weight the data (here by y^(-2)) use sth like the following: # fit f(x) "data.dat" using 1:2:(1./$2**2) via b f05(x)=a05*exp(b05*x)+0 fit [0.003:0.006] f05(x) "V6_05.dat" using (1./(($3/2+$4/2)+273.15)):($2*5380716) via a05,b05 a=1; b=1 f(x)=a*exp(b*x) fitLow =0.0030 fitHigh=0.0055 fit [fitLow:fitHigh] f(x) "data.dat" via a,b print a,b set output "png/fit.png" plot \ "data.dat" title "5V" with points pointsize 0.2\ , (x<=fitLow)||(x>=fitHigh)?1/0:f(x) notitle with lines \ unset output
Interpolate
smooth csplines
Advanced Fitting
FIT_LIMIT = 1e-8 # or even smaller
f(x) = a *exp(-(x-b )*(x-b )/c /c ) g(x) = A(a)*exp(-(x-B(b))*(x-B(b))/C(c)/C(c)) # trick: use atan as restriction function A(x) = (2.0-1.1)/pi*(atan(x)+pi/2)+1.1 # Restrict a to the range of [1.1:2.0] B(x) = (0.9-0.1)/pi*(atan(x)+pi/2)+0.1 # Restrict b to the range of [0.1:0.9] C(x) = (1.5-0.5)/pi*(atan(x)+pi/2)+0.5 # Restrict c to the range of [0.5:1.5] a =0.0 ; b =0.5 ; c =0.9 ; fit f(x) 'data.dat' via a, b, c aa=1.5 ; bb=0.5 ; cc=0.9 ; fit g(x) 'data.dat' via aa, bb, cc plot "data.dat" , f(x) , g(x) print A(aa), B(bb), C(cc) # do NOT use aa, bb, cc as they are not what you want!!!
Misc
Errorbars
plot data u ($1):($5):(0.1*$1):(0.1*$5) w xyerrorbars ps 0 plot data u ($1):($5):(0.1*$1) w xerrorbars plot data u ($1):($5):(0.1*$5) w yerrorbars
Dashed lines
In terminal mp (which I prefere) use terminal option dashed and redefine the linestyles using lt 1 (solid) as template
set style line 1 lt 1 linecolor rgb "red" set style line 2 lt 1 linecolor rgb "blue" set style line 3 lt 1 linecolor rgb "magenta"
Furthermore define how your dashed (e.g. lt 6 as template) line shall look like and define e.g. ls 30 to it
set style line 30 lt 6 lw 1 linecolor rgb "dark-green"
Now you can plot data and line by
plot data u 1:5 ls 2 set arrow from 0.55, graph 0 to 0.55, graph 1 nohead ls 30 back
number or Points to plot for analytic function
set samples 200 # default = 100
pause
you can use
pause mouse
to let gnuplot stop continuing until you click the mouse
Find min / max value
using Perl
max=`! perl -e '$max=-1e38; while (<>) {@t=split; $max=$t[1] if $t[1]>$max}; print $max' < 22.5.dat`
min=`! perl -e '$min=+1e38; while (<>) {@t=split; $min=$t[1] if $t[1]<$min}; print $min' < 22.5.dat`
print min,max
Version 2
s = '$col=2; $f='."'".data."'".'; use warnings; \
open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
@t=split /\t/ , shift @a ; $x=$t[$col-1]; print $x '
first=system("perl -e \"".s."\"")
print first
s = '$col=2; $f='."'".data."'".'; use warnings; \
open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
@t=split /\t/ , pop @a ; $x=$t[$col-1]; print $x '
last=system("perl -e \"".s."\"")
print last
s = '$col=2; $f='."'".data."'".'; use warnings; $x=1e38;\
open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
while ($l=shift @a) { @t=split /\t/,$l ; next if $#t<$col-1 ; $x=$t[$col-1] if $t[$col-1]<$x;} ; print $x '
min=system("perl -e \"".s."\"")
print min
s = '$col=2; $f='."'".data."'".'; use warnings; $x=-1e38;\
open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
while ($l=shift @a) { @t=split /\t/,$l ; next if $#t<$col-1 ; $x=$t[$col-1] if $t[$col-1]>$x;} ; print $x '
max=system("perl -e \"".s."\"")
print max
Version 2a - Linux
s = '$col=5; $f="'.data.'"; use warnings; $x=1e38;\
open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
while ($l=shift @a) { @t=split /\t/,$l ; next if $#t<$col-1 ; $x=$t[$col-1] if $t[$col-1]<$x;} ; print $x '
min=system("perl -e \"".s."\"")
print min
Version 3 (when using Perl to gen Gnuplot script)
my $colX=3; my $colY=2;
open (FH, $f);
my @a = grep {not m/^#/ and not m/^\s*$/} <FH>;
close FH;
my @b=split /\t/ , pop @a ;
my $lastX=$b[$colX-1];
my $lastY=$b[$colY-1];
$cont .= "set object 1 circle at $lastX , ($lastY*1E9) behind\n";
Variables
a=123 print "Variable a=",a undef a
Export (fit-)Variables
a=12
system(sprintf("echo A=%d >testausgabe.txt",a))
Schnippsel
c0C = 273.15 ckb = 1.38e-23 ce = 1.602e-19 ckbeV = ckb/ce
set x2tics (\ "25" (c0C+25) \ , "50" (c0C+50) \ , "75" (c0C+75) \ , "100" (c0C+100) \ , "125" (c0C+125) \ )
WARNING: you have to set x2 AND x ranges to the same! (so no autorange :-()
Multiplot advanced
Plots 3 graphs using same x-axis
Problem: commands size and origin include margins, so complicated to paint 3 graphs of same size of plot area
# set axis position to fixed position
set lmargin 8
set rmargin 10
set size 1.0,1.0
set grid xtics x2tics ytics y2tics -1
set key center top box
xmin = 1E-3
xmax = 1
set samples 1000
set logscale x
set logscale x2
set xrange [xmin:xmax]
set x2range [xmin:xmax]
set xlabel "Doping (MR)"
set multiplot
# plot 1(bottom)
set size 1.0 , 1.0/3
set origin 0.0,0.0
set bmargin 4 ; set tmargin 0 ; set xlabel "Doping (MR)"
set xtics mirror (1E-3, 1E-2, 1E-1, 1)
set ylabel "Cond." ; set ytics 0.5 mirror
unset y2tics ; unset y2label
plot sin(x)
# plot 2(middle)
set size 1.0 , 1.0/3
set origin 0.0 , 1.0/3
set bmargin 0 ; set tmargin 0; unset xlabel
set xtics mirror ("" 1E-3, "" 1E-2, "" 1E-1, "" 1)
unset ytics ; unset ylabel
set y2label "Seebeck" ; set y2tics 0.5
plot cos(x) with lines lc 2
# plot 2(top)
set size 1.0 , 1.0/3
set origin 0.0 , 1.0/3*2
set bmargin 0 ; set tmargin 2
unset xtics; set x2tics mirror (1E-3, 1E-2, 1E-1, 1)
set ylabel "Eact" ; set ytics 0.2
unset y2tics ; unset y2label
plot sin(x)*cos(x) with lines lc 3
unset multiplot
My Plot Template
allowing to choose between Terminal PNG or MetaPost
Main file plot.gp
#!/usr/bin/gnuplot load "/MessSoftware/A_gnuplot-header.gp" term = "png" term = "mp" plotfolder = "png_XYZ" data1 = "data/Eins.dat" data2 = "data/Zwei.dat" set style data linespoints set style increment user set style line 1 linetype 1 lw 2 ps 2 set style line 2 linetype 2 lw 2 ps 2 if (term eq "mp" ) set terminal mp color solid latex psnfss prologues 2 if (term eq "png" ) set terminal png enhanced giant size 1024,768 data = data1 load "plot_c_vs_d1.gp" # in here is the plot function data = data2 load "plot_c_vs_d1.gp" # again... if (term eq "mp" ) s = "perl convert.pl " . plotfolder ; system (s)
plot file plot1.gp, executed for each data set
f(x) = m*x+b
fit f(x) data using (log($1)):(log($2)) via m,b
fe(x) = x**m * exp(b)
set label 1 sprintf("m=%.2f",m) at graph 0.05, graph 0.75
set output plotfolder . "/" . "." . term
plot \
data u ($1):($2) notitle \
, fe(x) title "fit" w lines lw 1
unset output ; unset label 1
perl script convert.pl for converting .mp to png and .mps
#!/usr/bin/perl -w
use warnings;use strict;
my $del_mps = 1;
my $dpi = 222.841; # -> 28cm in ooimpress
my $plotdir = "png";
$plotdir = shift if @ARGV;
chdir $plotdir or die $!;
my @a = <*.mp>;
foreach my $f (@a) {
print "-->$f\n";
$_ = $f;
$f =~ s/ /_/g;
`mv "$_" "$f"` unless ($_ eq $f);
my $fname = $f;
$fname =~ s/\.[^\.]*?$//; # remove ext
print system("mpost -tex=latex '$fname.mp'");
print "\n";
my @b = grep {m/\.[\d]+$/} grep {-f $_} <$fname.*>;
$f = $b[0];
print `mv "$f" "$fname.mps"`;
print `convert -density $dpi "$fname.mps" "$fname.png"`;
print `rm "$fname.mps"` if $del_mps;
unlink ( split " ", "$fname.eps $fname.mp $fname.mpx $fname.log");
print "\n";
}
$_ = "mpxerr.tex"; unlink $_ if -f $_;
