使用风速和风速绘制风场

问题描述

如何使用下面的代码（如此地图）绘制风场？

Time  Temp Wind speed Wind direction Pressure
 202000200   10.8836    2.4982   90.5014   80.7499
 202000300    9.8425    2.6553   41.5163   90.0338
 202000400    9.5351    2.4581   40.1018   80.5542
 202000500   12.5231    4.1907  120.2293   84.4332
 202000600   17.2069    3.1405  177.5542   87.0220
 202000700   10.7297    5.5018  269.7194   81.5804
 202000800    6.0049    4.2357  309.8655   68.6385
 202000900    8.3194    2.5722   81.6993   78.4679
 202001000    8.5940    4.2101   41.0358   84.9437
 202001100    7.3084    3.8480  217.5551   70.2860
 202001200    5.5046    3.0959  158.0296   68.9129

解决方法

我不清楚第一列的解释方式（年份+某物？），因此出于说明目的，我仅将最后4位数字作为x坐标。
有许多用于定义箭头形状的选项。请参阅“帮助设置样式箭头”。
绘图样式with arrows的数据字段为 x：y：length：angle

set angle degrees
unset key
set xzeroaxis
set xrange [0:*]
set title "Wind speed and direction"

SCALE = 10.

plot $WIND using ($1 - 202000000) : (0) : ($3 * SCALE) : 4 with arrows noborder

这是gnuplot 5.2版本。您可以使用绘图样式with vectors。

特别要提到的是：

set size ratio -1使x和y具有相同的比例，例如45度角确实显示为45度角（选中help size）。因数SCALE取决于x和y范围，并且端子尺寸会自动调整。
要确保键（或图例）箭头的比例正确，我不使用标准键（因为我不知道其相对于坐标的比例），而是一个箭头和一个需要一些标签的标签额外的编码。

代码：

### plot wind directions (gnuplot 5.2)
reset session

$Data <<EOD
# Time  Temp Wind speed Wind direction Pressure
 202000200   10.8836    2.4982   90.5014   80.7499
 202000300    9.8425    2.6553   41.5163   90.0338
 202000400    9.5351    2.4581   40.1018   80.5542
 202000500   12.5231    4.1907  120.2293   84.4332
 202000600   17.2069    3.1405  177.5542   87.0220
 202000700   10.7297    5.5018  269.7194   81.5804
 202000800    6.0049    4.2357  309.8655   68.6385
 202000900    8.3194    2.5722   81.6993   78.4679
 202001000    8.5940    4.2101   41.0358   84.9437
 202001100    7.3084    3.8480  217.5551   70.2860
 202001200    5.5046    3.0959  158.0296   68.9129
EOD

set size ratio -1
set angle degrees
myTimeFmt = "%Y%j%H"

# automatic determination of "optimum" value for SCALE with given data and terminal size
plot x  # plot dummy graph otherwise GPVAL_TERM_XSIZE and GPVAL_TERM_YSIZE will be undefined
stats $Data u (timecolumn(1,myTimeFmt)):($3*sin($4)) nooutput
SCALE = (STATS_max_x-STATS_min_x)/(STATS_max_y-STATS_min_y)/GPVAL_TERM_XSIZE*GPVAL_TERM_YSIZE

set title "Wind speed and direction"
set format x "%j" timedate
set xzeroaxis lt -1
set grid xtics,mxtics lt -1,lt 0
set format y ""
unset ytics

# Legend arrow in correct scale
Speed = 2.0
KeyPosX = 0.8    # relative to graph
KeyPosY = 1.08   # relative to graph
set style arrow 1 filled size graph 0.015,15 fixed lc rgb "blue"
set arrow 1 from graph KeyPosX,graph KeyPosY rto first Speed*SCALE,0 as 1
set label 1 "2 m/s" at graph KeyPosX,graph KeyPosY right offset -1,0

plot $Data u (timecolumn(1,myTimeFmt)):(0):(SCALE*$3*cos($4)):(SCALE*$3*sin($4)) \
    w vectors as 1 notitle
### end of code

结果：

gnuplot