title: Wind rose chart with ggplot
body: <p>I am trying to use the fantastic wind rose R code from Andy Clifton at <a href="https://stackoverflow.com/a/17266781/709777">https://stackoverflow.com/a/17266781/709777</a> for plotting data extracted from a meteorological model. From the model I get u and v wind components in m/s. Then I compute wind speed and direction and try wind rose code. But I'm not sure it is working as expected or maybe I don't understand what the function is doing.</p>
  
  <p>My attempt uses Andy's function and the following code to plot 4 wind roses:</p>
  
  <pre><code>flist&lt;-c("03050","12010","46070","46050")
  
  for (i in 1:4 ) {
  
  windfile=paste("viento-",flist[i],".csv",sep="")
  viento=read.table(windfile,sep=";",header=F)
  colnames(viento) &lt;- c("u","v")
  fecha=read.table("ffhh.txt",header=F,sep=";")
  colnames(fecha) &lt;- c("date","hr")
  
  wind&lt;-cbind.data.frame(fecha,viento)
  
  wind$speed=sqrt(wind$u*wind$u+wind$v*wind$v)
  wind$dir=windDir(wind$u,wind$v)
  
  graf=paste("RAMS-wind-rose-",flist[i],".png",sep="")
  png(graf,res=240,width=3000, height=2400)
  plot.windrose(data = wind,spd = "speed",dir = "dir")
  dev.off()
  
  }
  </code></pre>
  
  <p>Graphical output is
  <img src="https://i.stack.imgur.com/7E7mT.png" alt="enter image description here"></p>
  
  <p>So maximum wind speed is in the 18-20 m/s range from the plot. Is it right? But if I look for maximum wind speed I get a different value</p>
  
  <pre><code>max(wind$speed)
  [1] 10.24317
  </code></pre>
  
  <p>Maybe I'm misunderstanding how <code>wind.rose</code> function runs or maybe there is a problem when calling the function. Any suggestion would be appreciated, I'm stuck here now.</p>
  
  <p>Wind data:</p>
  
  <pre><code>dput(wind)
  
  structure(list(date = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
  1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
  2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 
  3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
  3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
  4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 5L, 1L, 1L, 
  1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 
  2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
  2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
  3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 
  4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
  4L, 4L, 5L), .Label = c("05/05/2015", "05/06/2015", "05/07/2015", 
  "05/08/2015", "05/09/2015"), class = "factor"), hr = c(12L, 13L, 
  14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 0L, 1L, 2L, 
  3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 
  17L, 18L, 19L, 20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 
  7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 
  20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 
  11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 
  0L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 
  0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 
  15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 
  4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 
  18L, 19L, 20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 
  8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 
  21L, 22L, 23L, 0L), u = c(1.967012, 1.520496, 2.145498, 2.36543, 
  2.352827, 2.295602, 2.320738, 2.38692, 2.412154, 2.612796, 3.032838, 
  3.62067, 4.216179, 4.614041, 4.746128, 4.687606, 4.449001, 4.098231, 
  3.565422, 2.594458, -1.378813, -3.703259, -3.874501, -3.617813, 
  -3.360489, -3.179794, -3.073682, -3.053857, -3.100727, -3.193508, 
  -3.409015, -3.93074, -4.45107, -4.840204, -5.139567, -5.436072, 
  -5.776207, -6.371346, -7.121193, -7.59635, -7.894677, -7.906566, 
  -7.483042, -6.81692, -5.891807, -4.977591, -4.057455, -3.212969, 
  -2.421152, -1.546586, -0.455518, 0.639647, 2.054146, 3.487688, 
  5.05859, 7.112991, 8.424683, 9.222707, 9.661589, 9.87525, 9.978607, 
  9.800485, 9.46149, 9.037914, 8.542727, 7.966156, 7.308363, 6.567787, 
  5.676618, 4.929429, 4.2488, 3.619122, 3.071927, 2.662167, 2.388519, 
  2.199777, 2.059402, 1.941171, 1.826771, 1.742619, 1.653258, 1.61614, 
  1.66758, 1.813451, 1.983155, 1.967012, 1.520496, 2.145498, 2.36543, 
  2.352827, 2.295602, 2.320738, 2.38692, 2.412154, 2.612796, 3.032838, 
  3.62067, 4.216179, 4.614041, 4.746128, 4.687606, 4.449001, 4.098231, 
  3.565422, 2.594458, -1.378813, -3.703259, -3.874501, -3.617813, 
  -3.360489, -3.179794, -3.073682, -3.053857, -3.100727, -3.193508, 
  -3.409015, -3.93074, -4.45107, -4.840204, -5.139567, -5.436072, 
  -5.776207, -6.371346, -7.121193, -7.59635, -7.894677, -7.906566, 
  -7.483042, -6.81692, -5.891807, -4.977591, -4.057455, -3.212969, 
  -2.421152, -1.546586, -0.455518, 0.639647, 2.054146, 3.487688, 
  5.05859, 7.112991, 8.424683, 9.222707, 9.661589, 9.87525, 9.978607, 
  9.800485, 9.46149, 9.037914, 8.542727, 7.966156, 7.308363, 6.567787, 
  5.676618, 4.929429, 4.2488, 3.619122, 3.071927, 2.662167, 2.388519, 
  2.199777, 2.059402, 1.941171, 1.826771, 1.742619, 1.653258, 1.61614, 
  1.66758, 1.813451, 1.983155), v = c(-2.766112, -0.478182, -0.192239, 
  -0.124549, -0.263261, -0.265564, -0.47101, -1.788897, -1.908823, 
  -1.305634, -0.531897, 0.247035, 0.92907, 1.397227, 1.65391, 1.787991, 
  1.82894, 1.81852, 1.755265, 1.585399, 1.592519, 2.354492, 2.532527, 
  2.313413, 2.016459, 1.792902, 1.670022, 1.599441, 1.599147, 1.650283, 
  1.745915, 2.0444, 2.540668, 3.210907, 3.841764, 4.323583, 4.700086, 
  4.940802, 5.083652, 5.159999, 5.12434, 5.00041, 4.663396, 4.229373, 
  3.665845, 3.217579, 2.847133, 2.461892, 2.082835, 1.615325, 0.950391, 
  0.172732, -0.249755, -0.452249, -0.756625, -1.250214, -1.653063, 
  -1.854439, -1.986611, -2.139991, -2.312994, -2.468648, -2.499339, 
  -2.647794, -2.835616, -3.010868, -3.093763, -3.025498, -2.79024, 
  -2.552279, -2.296148, -1.938917, -1.563025, -1.275801, -1.101657, 
  -1.015782, -1.001581, -0.981939, -0.963097, -0.956454, -0.849296, 
  -0.603197, -0.285416, 0.060993, 0.38673, -2.766112, -0.478182, 
  -0.192239, -0.124549, -0.263261, -0.265564, -0.47101, -1.788897, 
  -1.908823, -1.305634, -0.531897, 0.247035, 0.92907, 1.397227, 
  1.65391, 1.787991, 1.82894, 1.81852, 1.755265, 1.585399, 1.592519, 
  2.354492, 2.532527, 2.313413, 2.016459, 1.792902, 1.670022, 1.599441, 
  1.599147, 1.650283, 1.745915, 2.0444, 2.540668, 3.210907, 3.841764, 
  4.323583, 4.700086, 4.940802, 5.083652, 5.159999, 5.12434, 5.00041, 
  4.663396, 4.229373, 3.665845, 3.217579, 2.847133, 2.461892, 2.082835, 
  1.615325, 0.950391, 0.172732, -0.249755, -0.452249, -0.756625, 
  -1.250214, -1.653063, -1.854439, -1.986611, -2.139991, -2.312994, 
  -2.468648, -2.499339, -2.647794, -2.835616, -3.010868, -3.093763, 
  -3.025498, -2.79024, -2.552279, -2.296148, -1.938917, -1.563025, 
  -1.275801, -1.101657, -1.015782, -1.001581, -0.981939, -0.963097, 
  -0.956454, -0.849296, -0.603197, -0.285416, 0.060993, 0.38673
  ), speed = c(3.39418794480919, 1.59391534001653, 2.15409319694506, 
  2.36870672272888, 2.3675095028426, 2.31091167734728, 2.36805305783971, 
  2.98287437935442, 3.07605139180817, 2.92085314241781, 3.07912662176355, 
  3.62908770080374, 4.31732977949809, 4.82095609181519, 5.02604708299514, 
  5.01702719021105, 4.81026313434109, 4.48358253183333, 3.9740645765147, 
  3.04051020438429, 2.10647621736634, 4.38836641577991, 4.62876344229536, 
  4.29423457807535, 3.91905514350105, 3.65042291577839, 3.49807011330648, 
  3.44735465087797, 3.48880768402874, 3.59470823936422, 3.83009170353009, 
  4.43060811938948, 5.12513590367358, 5.80839896393705, 6.41672031330531, 
  6.94580799814341, 7.4468366246511, 8.06260344150201, 8.7495661264061, 
  9.1831434162002, 9.41194907391285, 9.3550994692978, 8.81720929923862, 
  8.02234343939033, 6.93915047316846, 5.92699137712567, 4.95672345372566, 
  4.04772553598005, 3.19377185226638, 2.2363369851212, 1.0539163634772, 
  0.662559150893715, 2.06927362843608, 3.51688736574617, 5.11486208794773, 
  7.22202714006788, 8.58533056628911, 9.4072986777592, 9.86371761914553, 
  10.1044606012682, 10.243170354167, 10.1066180883186, 9.78603537991872, 
  9.41778649884526, 9.00105008851662, 8.51615920058802, 7.93621693503511, 
  7.23114542969321, 6.32530087628438, 5.55098174739226, 4.82955454238836, 
  4.10578167755825, 3.4467060570861, 2.95208423448417, 2.63033670069252, 
  2.42297996715883, 2.29004390725702, 2.17539629745065, 2.06510244730134, 
  1.98784436847481, 1.85864620360627, 1.72503771564827, 1.69182899533493, 
  1.8144764190945, 2.02051078861881, 3.39418794480919, 1.59391534001653, 
  2.15409319694506, 2.36870672272888, 2.3675095028426, 2.31091167734728, 
  2.36805305783971, 2.98287437935442, 3.07605139180817, 2.92085314241781, 
  3.07912662176355, 3.62908770080374, 4.31732977949809, 4.82095609181519, 
  5.02604708299514, 5.01702719021105, 4.81026313434109, 4.48358253183333, 
  3.9740645765147, 3.04051020438429, 2.10647621736634, 4.38836641577991, 
  4.62876344229536, 4.29423457807535, 3.91905514350105, 3.65042291577839, 
  3.49807011330648, 3.44735465087797, 3.48880768402874, 3.59470823936422, 
  3.83009170353009, 4.43060811938948, 5.12513590367358, 5.80839896393705, 
  6.41672031330531, 6.94580799814341, 7.4468366246511, 8.06260344150201, 
  8.7495661264061, 9.1831434162002, 9.41194907391285, 9.3550994692978, 
  8.81720929923862, 8.02234343939033, 6.93915047316846, 5.92699137712567, 
  4.95672345372566, 4.04772553598005, 3.19377185226638, 2.2363369851212, 
  1.0539163634772, 0.662559150893715, 2.06927362843608, 3.51688736574617, 
  5.11486208794773, 7.22202714006788, 8.58533056628911, 9.4072986777592, 
  9.86371761914553, 10.1044606012682, 10.243170354167, 10.1066180883186, 
  9.78603537991872, 9.41778649884526, 9.00105008851662, 8.51615920058802, 
  7.93621693503511, 7.23114542969321, 6.32530087628438, 5.55098174739226, 
  4.82955454238836, 4.10578167755825, 3.4467060570861, 2.95208423448417, 
  2.63033670069252, 2.42297996715883, 2.29004390725702, 2.17539629745065, 
  2.06510244730134, 1.98784436847481, 1.85864620360627, 1.72503771564827, 
  1.69182899533493, 1.8144764190945, 2.02051078861881), dir = c(324.582958174723, 
  287.457881896944, 275.120092612918, 273.014060101878, 276.384347431893, 
  276.598861790546, 281.472746249524, 306.85002863764, 308.355818041581, 
  296.551646657085, 279.947330562416, 266.096810627237, 257.573002083306, 
  253.152602628538, 250.787798573866, 249.121675592407, 247.652924389215, 
  246.071562949111, 243.788876501029, 238.572092345486, 139.113779336087, 
  122.447759192368, 123.170217537641, 122.596909573894, 120.965832554958, 
  119.416137865804, 118.516536815783, 117.643054658187, 117.281647992718, 
  117.328194221248, 117.119095146817, 117.479195348135, 119.717697802906, 
  123.559602263005, 126.777668542303, 128.497005101731, 129.135167930612, 
  127.79258494314, 125.522147782669, 124.187227469739, 122.987117968321, 
  122.310801292645, 121.930963285117, 121.816410282942, 121.889612313365, 
  122.879148352072, 125.057498240586, 127.460629717786, 130.704294359997, 
  136.24539694722, 154.39181584582, 254.888144850326, 276.932326801277, 
  277.388325995937, 278.506798594382, 279.968762057109, 281.101348461141, 
  281.369043841337, 281.619184732637, 282.227081687741, 283.050420058574, 
  284.138138210954, 284.797200895241, 286.328746582848, 288.362726758368, 
  290.704458912889, 292.943824332615, 294.733498374596, 296.175598342547, 
  297.373477244996, 298.387794419952, 298.179840415319, 296.9674148962, 
  295.605326053392, 294.760576510127, 294.785882352792, 295.935765474742, 
  296.832512250004, 297.798770744004, 298.760625478154, 297.190041875953, 
  290.467240727854, 279.712395757604, 268.073659209118, 258.965379766511, 
  324.582958174723, 287.457881896944, 275.120092612918, 273.014060101878, 
  276.384347431893, 276.598861790546, 281.472746249524, 306.85002863764, 
  308.355818041581, 296.551646657085, 279.947330562416, 266.096810627237, 
  257.573002083306, 253.152602628538, 250.787798573866, 249.121675592407, 
  247.652924389215, 246.071562949111, 243.788876501029, 238.572092345486, 
  139.113779336087, 122.447759192368, 123.170217537641, 122.596909573894, 
  120.965832554958, 119.416137865804, 118.516536815783, 117.643054658187, 
  117.281647992718, 117.328194221248, 117.119095146817, 117.479195348135, 
  119.717697802906, 123.559602263005, 126.777668542303, 128.497005101731, 
  129.135167930612, 127.79258494314, 125.522147782669, 124.187227469739, 
  122.987117968321, 122.310801292645, 121.930963285117, 121.816410282942, 
  121.889612313365, 122.879148352072, 125.057498240586, 127.460629717786, 
  130.704294359997, 136.24539694722, 154.39181584582, 254.888144850326, 
  276.932326801277, 277.388325995937, 278.506798594382, 279.968762057109, 
  281.101348461141, 281.369043841337, 281.619184732637, 282.227081687741, 
  283.050420058574, 284.138138210954, 284.797200895241, 286.328746582848, 
  288.362726758368, 290.704458912889, 292.943824332615, 294.733498374596, 
  296.175598342547, 297.373477244996, 298.387794419952, 298.179840415319, 
  296.9674148962, 295.605326053392, 294.760576510127, 294.785882352792, 
  295.935765474742, 296.832512250004, 297.798770744004, 298.760625478154, 
  297.190041875953, 290.467240727854, 279.712395757604, 268.073659209118, 
  258.965379766511)), .Names = c("date", "hr", "u", "v", "speed", 
  "dir"), row.names = c(NA, -170L), class = "data.frame")
  </code></pre>