This function will plot data by month laid out in a conventional calendar format. The main purpose is to help rapidly visualise potentially complex data in a familiar way. Users can also choose to show daily mean wind vectors if wind speed and direction are available.
Usage
calendarPlot(
mydata,
pollutant = "nox",
year = 2003,
month = 1:12,
type = "default",
annotate = "date",
statistic = "mean",
cols = "heat",
limits = c(0, 100),
lim = NULL,
col.lim = c("grey30", "black"),
col.arrow = "black",
font.lim = c(1, 2),
cex.lim = c(0.6, 1),
digits = 0,
data.thresh = 0,
labels = NA,
breaks = NA,
w.shift = 0,
remove.empty = TRUE,
main = NULL,
key.header = "",
key.footer = "",
key.position = "right",
key = TRUE,
auto.text = TRUE,
...
)
Arguments
- mydata
A data frame minimally containing
date
and at least one other numeric variable. The date should be in eitherDate
format or classPOSIXct
.- pollutant
Mandatory. A pollutant name corresponding to a variable in a data frame should be supplied e.g.
pollutant = "nox".
- year
Year to plot e.g.
year = 2003
. If not supplied all data potentially spanning several years will be plotted.- month
If only certain month are required. By default the function will plot an entire year even if months are missing. To only plot certain months use the
month
option where month is a numeric 1:12 e.g.month = c(1, 12)
to only plot January and December.- type
Not yet implemented.
- annotate
This option controls what appears on each day of the calendar. Can be: “date” --- shows day of the month; “wd” --- shows vector-averaged wind direction, or “ws” --- shows vector-averaged wind direction scaled by wind speed. Finally it can be “value” which shows the daily mean value.
- statistic
Statistic passed to
timeAverage
.- cols
Colours to be used for plotting. Options include “default”, “increment”, “heat”, “jet” and
RColorBrewer
colours --- see theopenair
openColours
function for more details. For user defined the user can supply a list of colour names recognised by R (typecolours()
to see the full list). An example would becols = c("yellow", "green", "blue")
- limits
Use this option to manually set the colour scale limits. This is useful in the case when there is a need for two or more plots and a consistent scale is needed on each. Set the limits to cover the maximimum range of the data for all plots of interest. For example, if one plot had data covering 0--60 and another 0--100, then set
limits = c(0, 100)
. Note that data will be ignored if outside the limits range.- lim
A threshold value to help differentiate values above and below
lim
. It is used whenannotate = "value"
. See next few options for control over the labels used.- col.lim
For the annotation of concentration labels on each day. The first sets the colour of the text below
lim
and the second sets the colour of the text abovelim
.- col.arrow
The colour of the annotated wind direction / wind speed arrows.
- font.lim
For the annotation of concentration labels on each day. The first sets the font of the text below
lim
and the second sets the font of the text abovelim
. Note that font = 1 is normal text and font = 2 is bold text.- cex.lim
For the annotation of concentration labels on each day. The first sets the size of the text below
lim
and the second sets the size of the text abovelim
.- digits
The number of digits used to display concentration values when
annotate = "value"
.- data.thresh
Data capture threshold passed to
timeAverage
. For example,data.thresh = 75
means that at least 75% of the data must be available in a day for the value to be calculate, else the data is removed.- labels
If a categorical scale is required then these labels will be used. Note there is one less label than break. For example,
labels = c("good", "bad", "very bad")
.breaks
must also be supplied if labels are given.- breaks
If a categorical scale is required then these breaks will be used. For example,
breaks = c(0, 50, 100, 1000)
. In this case “good” corresponds to values berween 0 and 50 and so on. Users should set the maximum value ofbreaks
to exceed the maximum data value to ensure it is within the maximum final range e.g. 100--1000 in this case.- w.shift
Controls the order of the days of the week. By default the plot shows Saturday first (
w.shift = 0
). To change this so that it starts on a Monday for example, setw.shift = 2
, and so on.- remove.empty
Should months with no data present be removed? Default is
TRUE
.- main
The plot title; default is pollutant and year.
- key.header
Adds additional text/labels to the scale key. For example, passing
calendarPlot(mydata, key.header = "header", key.footer = "footer")
adds addition text above and below the scale key. These arguments are passed todrawOpenKey
viaquickText
, applying theauto.text
argument, to handle formatting.- key.footer
see
key.header
.- key.position
Location where the scale key is to plotted. Allowed arguments currently include
"top"
,"right"
,"bottom"
and"left"
.- key
Fine control of the scale key via
drawOpenKey
. SeedrawOpenKey
for further details.- auto.text
Either
TRUE
(default) orFALSE
. IfTRUE
titles and axis labels will automatically try and format pollutant names and units properly e.g. by subscripting the `2' in NO2.- ...
Other graphical parameters are passed onto the
lattice
functionlattice:levelplot
, with common axis and title labelling options (such asxlab
,ylab
,main
) being passed to viaquickText
to handle routine formatting.
Value
As well as generating the plot itself, calendarPlot
also
returns an object of class ``openair''. The object includes three main
components: call
, the command used to generate the plot;
data
, the data frame of summarised information used to make the
plot; and plot
, the plot itself. If retained, e.g. using
output <- calendarPlot(mydata, "nox")
, this output can be used to
recover the data, reproduce or rework the original plot or undertake
further analysis.
An openair output can be manipulated using a number of generic operations,
including print
, plot
and summary
.
Details
calendarPlot
will plot data in a conventional calendar format i.e. by
month and day of the week. Daily statistics are calculated using
timeAverage
, which by default will calculate the daily mean
concentration.
If wind direction is available it is then possible to plot the wind
direction vector on each day. This is very useful for getting a feel for the
meteorological conditions that affect pollutant concentrations. Note that if
hourly or higher time resolution are supplied, then calendarPlot
will
calculate daily averages using timeAverage
, which ensures that
wind directions are vector-averaged.
If wind speed is also available, then setting the option annotate =
"ws"
will plot the wind vectors whose length is scaled to the wind speed.
Thus information on the daily mean wind speed and direction are available.
It is also possible to plot categorical scales. This is useful where, for
example, an air quality index defines concentrations as bands e.g.
“good”, “poor”. In these cases users must supply labels
and corresponding breaks
.
Note that is is possible to pre-calculate concentrations in some way before
passing the data to calendarPlot
. For example
rollingMean
could be used to calculate rolling 8-hour mean
concentrations. The data can then be passed to calendarPlot
and
statistic = "max"
chosen, which will plot maximum daily 8-hour mean
concentrations.
Examples
# load example data from package
data(mydata)
# basic plot
calendarPlot(mydata, pollutant = "o3", year = 2003)
# show wind vectors
calendarPlot(mydata, pollutant = "o3", year = 2003, annotate = "wd")
if (FALSE) {
# show wind vectors scaled by wind speed and different colours
calendarPlot(mydata, pollutant = "o3", year = 2003, annotate = "ws",
cols = "heat")
# show only specific months with selectByDate
calendarPlot(selectByDate(mydata, month = c(3,6,10), year = 2003),
pollutant = "o3", year = 2003, annotate = "ws", cols = "heat")
# categorical scale example
calendarPlot(mydata, pollutant = "no2", breaks = c(0, 50, 100, 150, 1000),
labels = c("Very low", "Low", "High", "Very High"),
cols = c("lightblue", "green", "yellow", "red"), statistic = "max")
}