gnuplot - 如何使用矢量从风向角度绘制箭头

Question

我希望有人能帮助我。我正在尝试绘制风的角度并为风的强度着色。风强度的调色板很好，但我在将角度转换为矢量并正确绘制箭头时遇到困难 - 理想情况下没有“尾部”/线。这是数据文件的示例:

"Date", "Temp", "icon", "rain", "snow", "wind.speed", "wind.deg", "clouds.all"
"2019-12-29 18:00:00",5.58,"04n",,,"n",2.45,185,51,1025
"2019-12-29 21:00:00",5.36,"04n",,,"n",2.51,182,99,1025
"2019-12-30 00:00:00",5.34,"04n",,,"n",2.6,196,95,1025
"2019-12-30 03:00:00",5.28,"03n",,,"n",2.72,207,47,1024
"2019-12-30 06:00:00",5.23,"02n",,,"n",2.62,200,23,1024
"2019-12-30 09:00:00",5.47,"01d",,,"d",2.48,214,0,1024
"2019-12-30 12:00:00",9.82,"01d",,,"d",3.96,215,0,1023
"2019-12-30 15:00:00",8.94,"01d",,,"d",3.24,218,0,1021
"2019-12-30 18:00:00",6.18,"01n",,,"n",2.88,214,0,1022
"2019-12-30 21:00:00",5.75,"01n",,,"n",2.13,232,0,1022
"2019-12-31 00:00:00",5.82,"03n",,,"n",0.8,216,33,1022
"2019-12-31 03:00:00",5.18,"04n",,,"n",0.32,8,66,1022
"2019-12-31 06:00:00",5.37,"04n",,,"n",1.79,58,83,1022
"2019-12-31 09:00:00",5.1,"04d",,,"d",3.88,66,100,1023
"2019-12-31 12:00:00",7.97,"04d",,,"d",4.39,84,100,1025
"2019-12-31 15:00:00",8.52,"04d",,,"d",3.97,74,100,1025
"2019-12-31 18:00:00",7.83,"04n",,,"n",2.97,58,100,1026
"2019-12-31 21:00:00",7.93,"04n",,,"n",4.08,72,100,1027

这是我到目前为止的代码 - 大部分来自这里:http://www.gnuplotting.org/vector-field-from-data-file/

#!/usr/bin/gnuplot
reset

set datafile missing "?"
set datafile separator ","

set terminal pngcairo true transparent truecolor size 1800, 500
set output '~/meteogram/vector.png'

set xdata time
set timefmt "%Y-%m-%d %H:%M:%S"

set palette defined ( 0 '#ffffff', \
1 '#ffee00',\
2 '#ff7000',\
3 '#ee0000',\
4 '#7f0000')

xf(phi) = 10*cos(phi/180.0*pi+pi/2)
yf(phi) = 10*sin(phi/180.0*pi+pi/2)

plot FILE every 1 using 1:($7-yf($8)):(2*xf($8)):(2*yf($8)):7 with vectors head fixed filled lc palette

我正在尝试从网站获取类似此图片的情节 因此，只需旋转一个箭头来指示风向(按强度着色)，但以相同的 y 值绘制我应该补充一点，我在 Ubuntu 上使用 Gnuplot 5.2

Answer 1

 set datafile missing "?"
 set datafile separator ","
 set xdata time
 set timefmt "%Y-%m-%d %H:%M:%S"
 set ang deg
 unset key
 unset colorbox

 plot 'wind.dat' using 1:7:("➤"):8:7 with labels rotate variable textcolor palette

此示例使用 unicode 字形 U+27A4“BLACK RIGHTWARDS ARROWHEAD”。其他可能的字符:→🠆🠊🠞🠮🢚🢡

精确的外观取决于字体和字体大小。