Pie chart gnuplot

Question

Does anyone have example code in gnuplot for a pie chart? I can't find any great example with a simple graph and the text around it and in it with the % signs that shows easily how much each part has of the circle.

Some example data:

Management frames   4596
Control frames  70173
Data frames 40347
TCP packets 36864
HTTP packets    525
ICMP packets    47
Total frames    115116

Answer 1

Updated: After some years, I came again across this post, and I thought the code looked pretty messy. Therefore an attempt to improve and clean it up.

The following code is a bit different from the link I referenced above.

• instead of a predefined color sequence or number codes in a separate list, the colors of the sections are given in the datablock (or datafile) next to the item/number by the names of predefined colors in gnuplot (see also https://stackoverflow.com/a/55736522/7295599). Because palette is used you can enter either colorname or hex-code, e.g. magenta or 0xff00ff.

• the labels are aligned left or right depending on their position relative to 0.

• you can choose the starting angle by PieStart and "rotation"-direction by PieDirection of the pie-chart

• you can add individual radial and angular offsets for segments and labels

• as you can see, there is no need for the total sum in the raw data. The total sum will be calculated automatically.

• the reason why I define various functions f(n) which actually do not depend on n is to get the current values of other variables (at the time of calling the function) instead of passing a lot of parameters to the functions.

I hope you can adapt this code to your needs.

Code: (works with gnuplot>=5.0.0)

### pie-chart with labels with gnuplot
reset session

set size square
set angle degrees
set border 0
unset colorbox
unset tics
unset key 

$Data <<EOD
# label     value   color      SRoff   SAoff   LRoff   LAoff
"Alpha"     85843   red          0       0      0      0
"Beta"      44000   green        0.2    45      0.2    0
"Gamma"     25399   blue         0       0      0      0
"Delta"     18451   magenta      0       0      0      0
"Epsilon"   12344   yellow       0       0      0      0
"Zeta"      11999   cyan         0       0      0      0
"Eta"       9000    orange       0       0      0      0
"Theta"     8500    0xb0f060     0       0      0.03   0
"Iota"      4711    dark-violet  0       0      0.12   0
EOD

colLabel   = 1     # label
colValue   = 2     # segment value
colColor   = 3     # segment color, either color name or 0xRRGGBB value
colSegRoff = 4     # radial  segment offset
colSegAoff = 5     # angular segment offset
colLabRoff = 6     # radial  label   offset
colLabAoff = 7     # angular label   offset

# define a palette from colornames of the datafile/datablock in column colColor
set table $Dummy
    myPalette = ''
    plot $Data u (myPalette = myPalette.(myPalette eq '' ? '' : ', ').sprintf('%d "%s"',$0,strcol(colColor)),$0) with table
    myPalette = '('.myPalette.')'
unset table
set palette defined @myPalette

stats $Data u colValue nooutput    # get total sum from column colValue
TotalSum = STATS_sum

set xrange[-1.5:1.5]
set yrange[-1.5:1.5]

PieStart       = 90      # 0 = 3 o'clock, 90 = 12 o'clock
PieDirection   = -1      # -1 clockwise, 1 counterclockwise
Radius         = 1.0
RadiusLabelOff = 0.05    # default radial label offset
SegPosX(n)     = column(colSegRoff)*cos((a2+a1+column(colSegAoff))*0.5)
SegPosY(n)     = column(colSegRoff)*sin((a2+a1+column(colSegAoff))*0.5)
LabPosX(n)     = (Radius+RadiusLabelOff+column(colLabRoff))*cos((a2+a1+column(colLabAoff))*0.5)
LabPosY(n)     = (Radius+RadiusLabelOff+column(colLabRoff))*sin((a2+a1+column(colLabAoff))*0.5)
a1=a2=PieStart
getAngles(n)   = (a1=a2, a2=a2+sgn(PieDirection)*column(colValue)/TotalSum*360)
getLabel(n)    = sprintf("%s %.1f%%", strcol(colLabel),  column(colValue)/TotalSum*100)

set multiplot layout 2,1

    plot $Data u (getAngles(0), SegPosX(0)):(SegPosY(0)):(Radius):(PieDirection<0?a2:a1):(PieDirection<0?a1:a2):($0) \
           with circles fs solid 1.0 lc palette notitle,\
        '' u ( getAngles(0), Align=LabPosX(0)):(LabPosY(0)): (Align>0? getLabel(0) : '') with labels font ",10" left, \
        '' u ( getAngles(0), Align=LabPosX(0)):(LabPosY(0)): (Align<0? getLabel(0) : '') with labels font ",10" right

    PieDirection = +1
    a1=a2=PieStart
    replot

unset multiplot
### end of code

Result: