如何将 gnuplot polar 限制在 180 度范围内？

Question

我正在尝试使用 gnuplot 绘制扬声器在 +/- 90 度范围内的离轴响应。我的这个工作很好，几乎完全是 Creating a microphone polar pattern plot in gnuplot

的结果

我想对此进行扩展，使其仅显示前向“180 度范围，但我不知道该怎么做，希望得到一些指点。

到目前为止，这是我的代码

gnuplot <<EOF
set terminal pngcairo size ${WIDTH}/2,${HEIGHT}/2 font ',10'

set polar
set angle degrees
set size ratio 1
set tmargin 3
set bmargin 3

set style line 11 lc rgb 'gray80' lt -1
set grid polar ls 11

unset border
unset xtics
unset ytics

set xrange [-30:30]
set yrange [-30:30]
set key

r=1
set rrange [0:r]
set rtics 0.166 format '' scale 0
set label '0°' center at first 0, first r*1.05
set label '180°' center at first 0, first -r*1.05
set label '-90°' right at first -r*1.05, 0
set label '+90°' left at first r*1.05, 0

set for [i=1:5] label at first r*0.02, first r*((i/6.0) + 0.03) sprintf("%d dB", -30+(i*5))
unset raxis

set key outside top right
set style line 11 lw 2 

set output '${PREFIX}_polar.png'
set multiplot layout 1,2 title "Circular Polar Response"
set title "Normalised"
plot '${PREFIX}_norm_polar_1000.txt' t '1k'  w lp ls 11 lt 1 pt -1 , \
     '${PREFIX}_norm_polar_2000.txt' t '2k'  w lp ls 11 lt 2 pt -1 , \
     '${PREFIX}_norm_polar_4000.txt' t '4k'  w lp ls 11 lt 3 pt -1 , \
     '${PREFIX}_norm_polar_8000.txt' t '8k'  w lp ls 11 lt 4 pt -1 , \
     '${PREFIX}_norm_polar_16000.txt' t '16k' w lp ls 11 lt 5 pt -1 
set title "Unnormalised"
plot '${PREFIX}_polar_1000.txt' t '1k'  w lp ls 11 lt 1 pt -1 , \
     '${PREFIX}_polar_2000.txt' t '2k'  w lp ls 11 lt 2 pt -1 , \
     '${PREFIX}_polar_4000.txt' t '4k'  w lp ls 11 lt 3 pt -1 , \
     '${PREFIX}_polar_8000.txt' t '8k'  w lp ls 11 lt 4 pt -1 , \
     '${PREFIX}_polar_16000.txt' t '16k' w lp ls 11 lt 5 pt -1 

EOF

结果是

数据看起来像这样（这是示例图片中的 1k 行）

180 0.657067
172.5 0.6832
165 0.717767
157.5 0.7461
150 0.7747
142.5 0.806167
135 0.835633
127.5 0.865167
120 0.890533
112.5 0.918133
105 0.929633
97.5 0.9566
90 0.9632
82.5 0.9566
75 0.929633
67.5 0.918133
60 0.890533
52.5 0.865167
45 0.835633
37.5 0.806167
30 0.7747
22.5 0.7461
15 0.717767
7.5 0.6832
0 0.657067

Answer 1

如果您使用与 rrange 设置相矛盾的 xrange 和 yrange 设置，Gnuplot 会感到困惑。这可能就是忽略 yrange 设置的原因。

然后，您还必须使用 set size ratio -1 才能在 x 和 yrange 中获得相同的缩放比例。仅绘制上两个象限时，set size square.

的宽高比会错误

set terminal pngcairo font ',10'

set polar
set angle degrees
set size ratio 1
set lmargin 8
set style line 11 lc rgb 'gray80' lt -1
set grid polar ls 11

unset border
unset tics

set xrange [-1:1]
set yrange [0:1]
set size ratio -1

r = 1
set rtics 0.166 format '' scale 0
set label '0°' center at first 0, first r*1.05
set label '-90°' right at first -r*1.05, 0
set label '+90°' left at first r*1.05, 0

set for [i=1:5] label at first r*0.02, first r*((i/6.0) + 0.03) sprintf("%d dB", -30+(i*5))
unset raxis

set key outside top right

set output 'polar.png'
plot 'norm_polar_1000.txt' w lp ls 1 t '1k'

如何将 gnuplot polar 限制在 180 度范围内？

How do I limit a gnuplot polar to a 180 degree range?

gnuplot

polar-coordinates