Gnuplot SVG输出质量问题：多余白线与空g标签解决诉求

问题1：右侧纵轴旁多余白色竖线 #

这条竖线是坐标轴设置超出绘图范围或背景矩形边界不当导致的，可通过以下两步修复：

• 移除初始的set ytics "0",3600,"86400"指令，后续do for循环已生成0-23点的纵轴刻度，该指令中86400超出了yrange [0:86399]范围，会触发多余边界绘制。
• 将背景矩形的坐标系从graph改为screen，确保完全覆盖绘图区域且不超出：

  set object 1 rectangle from screen 0, screen 0 to screen 1, screen 1 behind fc rgbcolor 'white' fs noborder
  

问题2：SVG文件包含大量空<g>标签 #

空标签源于plot命令拆分了过多独立绘图项（每个filledcurve单独调用plot），可合并成对的filledcurve x1/x2来减少空标签：
原脚本中每对filledcurve x1和x2对应同一颜色的上下填充，可合并为单个filledcurve指令（使用using 1:col1:col2语法），大幅减少空标签生成。

完整修正后的脚本 #

set terminal svg size 1000,500 noenhanced
set output "dose.svg"
set xlabel "Päiväys" textcolor rgb "white"
set label 1 'Clock value' at graph -0.08, graph 0.3 rotate
set xdata time
set locale "fi_FI.utf8"
set timefmt "%m-%d"
set xtics out
set format x "%b"
set title "Pimeysdiagrammi LL" font "arial, 20"
set key off
datafile="./f.data"
set datafile missing NaN
set yrange [0:86399]
set ytics ("" 0)
do for [y = 0:23] {
   set ytics add (sprintf("%d",y) (y*3600))
}
set grid ytics lt 2 lc rgb "red" lw 1

set border lw 2 lc rgb "orange"

set xtics textcolor rgb "white"
set ytics textcolor rgb "white"

set ylabel "Kello" textcolor rgb "white"

set title textcolor rgb "white"

set object 1 rectangle from screen 0, screen 0 to screen 1, screen 1 behind fc rgbcolor 'white' fs noborder
plot datafile using 1:2:3 w filledcurve lc rgb "#BFD0FB", \
 '' using 1:4:5 w filledcurve lc rgb "#7FA2F7", \
 '' using 1:6:7 w filledcurve lc rgb "#3F74F3", \
 '' using 1:8:9 w filledcurve lc rgb "#0046F0", \
 '' using 1:10:11 w filledcurve lc rgb "#002EA0", \
 '' using 1:12:13 w filledcurve lc rgb "#001750", \
 '' using 1:14:15 w filledcurve lc rgb "black", \
 '' using 1:16 w impulse lc rgb "green", \
 '' u 1:17:((strcol(18) eq "New") ? ('UUSI'):NaN) w labels left font "Symbola,14" offset -0.5,0, \
 '' u 1:17:((strcol(18) eq "Full") ? ('VANHA'):NaN) w labels left font "Symbola,14" offset -0.5,0

数据示例 #

1-25 33780 54120 33540 54300 33240 54600 33060 54840 29160 58680 25380 62520 21840 66000 0 71640 Full

内容的提问来源于stack exchange，提问作者Timppa