Key features:
multiple data sets, Greek letters, subscripts, different types of error bars, custom ordinate magnitude label, legend with border, difference function, publication quality, vector file output (.eps)
This image is Fig. 1 from my second publication.
reset
set terminal postscript eps color enhanced "Helvetica" 25 size 4.676,3.5 ## good ratio for publication: 1.336
set output "fig1-v8.eps" ## output filename
set title ""
set xlabel "Temperature (K)" offset 0,.5
set ylabel "({/Symbol \147} - {/Symbol \147}_{IAPWS})/{/Symbol \147}_{ref}" offset 1.5,0
set tics scale 2.5
set xtic 203,5,350 offset 0,.1 nomirror ## this is the spacing between tics on the x-axis
set mxtics 2 ## this sets the frequency of the MINOR x-tics;
set ytic -10,1,10 offset .5,0 nomirror ## this is the spacing between tics on the y-axis
#set mytics 2 ## this sets the v of the MINOR y-tics
set xrange [246.5:274]
set yrange [-2:4.5]
set label "x 10^{-3}" at graph -.02,1.035 font "Helvetica,20"
unset grid ## alternatively, use "with lines" after "plot"
set samples 10000 ## default=100... improves smoothness
set border 15 lw 2
set key samplen 0.5 ###invert
set key spacing 2
###set key vertical
set key maxrows 4 ## selects multi-column legend
###set key maxcols 2 ## selects multi-column legend
###set key height -1 ## number of character spaces to lengthen/shorten legend by
###set key width +.5 ## number of character spaces to lengthen/shorten legend by
set key box lw 1.5 at 274, 4.5 ## legend; option: "nobox"
set pointsize 2
set bars small ## removes "caps" from errorbars
iapws(x) = B*((1-(x/Tc))**mu)*(1+b*(1-(x/Tc)))
B = 235.8
b = -.625
mu = 1.256
Tc = 647.096
sigref2015 = 71.19
sigref2014 = 72.74
zero(x) = 0
#----- Notice that I have rigged "small" x-error bars to be the horizontal lines.
#----- Also, the very last "plot" command is meaningless-- just in order to get a blank "title" space.
#----- The same plots appear twice in some cases for layering effects + legend ordering.
###set label "{/Symbol \163}_{ind} {/Symbol \364}" at graph .835,0.73
set label "{/Symbol \163}_{ind} {/Symbol \364}" at graph .835,0.81
plot zero(x) lc rgb "white" lw 2 notitle, \
zero(x) lc rgb "black" lw 2 notitle, \
"hruby_6errors.dat" u 1:(1000*((($2-iapws($1))/sigref2015)+$7)):($8*.7) with xerrorbars pt 0 lc rgb "black" lw 4 notitle, \
"hruby_6errors.dat" u 1:(1000*((($2-iapws($1))/sigref2015)-$7)):($8*.7) with xerrorbars pt 0 lc rgb "black" lw 4 notitle, \
"hruby_6errors.dat" u 1:(1000*(($2-iapws($1))/sigref2015)):(1000*($5/sigref2015)) with yerrorbars pt 0 lc rgb "black" lw 4 notitle, \
"hruby_jpcl5_prague.dat" u 1:(1000*(($2-iapws($1))/sigref2014)) pt 9 lt 4 ps 3 lw 3 title "h 2014", \
"hruby_jpcb199_p1.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 1 lt 1 ps 2.5 lw 3 title "p-1 2015", \
"hruby_jpcb199_p2.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 2 lt 2 lw 3 title "p-2 2015", \
"hruby_jpcb199_h1.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 64 lt 3 lw 3 title "h-1 2015", \
"hruby_jpcb199_h2.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 65 lt 7 lw 3 title "h-2 2015", \
"hruby_6errors.dat" u 1:(1000*((($2-iapws($1))/sigref2015)-$7)):($8*.7) with xerrorbars pt 0 lc rgb "black" lw 4 title "{/Symbol \163}_{Hru}", \
"hruby_6errors.dat" u 1:(1000*(($2-iapws($1))/sigref2015)):(1000*($5/sigref2015)) with yerrorbars pt 0 lc rgb "black" lw 4 notitle, \
"hruby_jpcl5_prague.dat" u 1:(1000*(($2-iapws($1))/sigref2014)) pt 9 lt 4 ps 3 lw 3 notitle, \
"hruby_jpcb199_p1.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 1 lt 1 ps 2.5 lw 3 notitle, \
"hruby_jpcb199_p2.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 2 lt 2 lw 3 notitle, \
"hruby_jpcb199_h1.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 64 lt 3 lw 3 notitle, \
"hruby_jpcb199_h2.dat" u 1:(1000*(($2-iapws($1))/sigref2015)) pt 65 lt 7 lw 3 notitle, \
"hruby_jpcb199_h1.dat" u 1:2 pt 0 lt 0 lw 0 title " "
##### EPS POINT TYPES #####
# 5 = filled box
# 7 = filled circle (dot)
# 8 = filled up triangle
# 11 = filled down triangle (small)
#
# 63 = filled diamond
# 64 = empty box
# 65 = empty circle
# 68 = empty diamond
# pointtype ("pt")
# 0 = none
# 1 = +
# 2 = X
# 3 = X & horz.line
# 4 = open box
# 5 = closed box
# 6 = open circle
# 7 = closed circ.
# 8 = open up triang.
# 9 = closed up triang.
# linetype ("lt")
# -1 = black
# 0 = grey dotted
# 1 = purple
# 2 = green
# 3 = sky blue
# 4 = orange
# 5 = yellow
# 6 = navy blue
# 7 = red