windrose {climatol}

Wind-rose plot

Description

This function plots a wind-rose from a data frame with columns DateTime, Wind direction and Wind speed.

Usage

windrose(dat, cols=1:3, code='', name='', uni='m/s', ndir=16, spdcut=NULL,
maxnsc=8, fnum=4, fint=5, flab=2, ang=-3*pi/16, margin=c(0,0,4,0),
pal=c('cyan','yellow','orange','red','brown'), ...)

Arguments

dat

Data frame with columns DateTime, Wind direction and Wind speed.

cols

Columns containing DateTime, Wind direction and Wind speed [1:3].

code

Station code.

name

Station name.

uni

Speed units for the legend header ['m/s'].

ndir

Number of classes of wind direction [16].

spdcut

Speed values to set the wind speed classes. If not provided, classes will be automatically calculated.

maxnsc

Maximum number of wind speed classes [8].

fnum

Number of reference circles to plot [4].

fint

Frequency interval (in %) between reference circles [5].

flab

Parameter indicating which circles must be labelled:

1:

Label outer circle only,

2:

Label all circles (the default),

Other value:

Do not label any circle.

ang

Angle along which circles will be labeled, in radians [-3*pi/16].

margin

Margins vector for the plot (to be passed to par) [c(0,0,4,0)].

pal

Color gradation to fill the frequency polygons.

...

Other graphic parameters.

Details

After reading the data, a frequency table is calculated in 16 wind directions and a variable number of wind speed classes, which can be set by the user. Calm observations (wind speed equal to zero) are distributed proportionally into the first wind speed class. The wind direction data must be provided in degrees.

This table, which covers all available pairs of wind direction and speed present in the data frame, is the basis of the wind-rose plot.

Value

The table of wind frequencies by direction and speed classes is returned invisibly.

Examples

data(climatol_data) #load example data
windtable <- windrose(AWS_1year, 1:3, 'st123', 'My airport') #plot windrose
print(windtable) #display the table of calculated wind frequencies