trendLevel(mydata, pollutant = "nox", x = "month", y = "hour",
type = "year", rotate.axis = c(90, 0), n.levels = c(10, 10, 4),
limits = c(0, 100), cols = "default", auto.text = TRUE,
key.header = "use.stat.name", key.footer = pollutant,
key.position = "right", key = TRUE, statistic = c("mean", "max",
"frequency"), stat.args = NULL, stat.safe.mode = TRUE,
drop.unused.types = TRUE, ...)
trendLevel
plot.mydata
to sample to produce the trendLevel
plot.trendLevel
x-axis. This is used with the y
and type
options to bin the data before applying
statistic
(see below). Allowed options currently
include trendLevel
y-axis and for additional conditioning,
respectively. As x
above.trendLevel
x
and y
axes. The
default, c(90, 0)
, rotates the x axis by 90
degrees but does not rotate the y axis. (Note: If only
one value is supplied, this is appliex
,
y
and type
data into if numeric. The
default, c(10, 10, 4)
, cuts numeric x
and
y
data into ten levels and numeric type
datatrendLevel
plot.trendLevel
surface. cols
is passed to
openColours
for evaluation. See
?openColours
for more details.auto.text = TRUE
passes common lattice
labelling terms (e.g. xlab
for the x-axis,
ylab
for the y-axis and main
for the title)
to the plot via key.header = "",
key.footer = c("mean","nox")
adds the addition text as a
scale footer. If enabled (auto.text = TRUE
drawOpenKey
. See ?drawOpenKey
for further
details.pollutant
measurements
with. Three options are currently encoded: statistic
if this is a function. The extra options
should be supplied as a list of named parameters. (see
Details below.)statistic
that most
users can ignore. This option returns NA
instead
of running statistic
on binned subsamples that are
empty. Many common funtype
conditioning cases. Some conditioning options may
generate empty cases for some data sets, e.g. a hour of
the day when no measurements were taken. Empty x
and y
cases generate 'holes' cutData
for type
handling and
levelplot
in lattice
for finer control of
the plot itself.trendLevel
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 <- trendLevel(mydata)
, 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
. See openair.generics
for
further details.
Summary statistics can also be extracted directly using
results
, e.g. results(object)
for
output <- trendLevel(mydata)
.
trendLevel
allows the use of third party summarising
functions via the statistic
option. Any additional
function arguments not included within a function called
using statistic
should be supplied as a list of
named parameters and sent using stat.args
. For
example, the encoded option statistic = "mean"
is
equivalent to statistic = mean, stat.args =
list(na.rm = TRUE)
or the R command mean(x, na.rm=
TRUE)
. Many R functions and user`s own code could be
applied in a similar fashion, subject to the following
restrictions: the first argument sent to the function must
be the data series to be analysed; the name `x' cannot be
used for any of the extra options supplied in
stat.args
; and the function should return the
required answer as a numeric or NA. Note: If the supplied
function returns more than one answer, currently only the
first of these is retained and used by trendLevel
.
All other returned information will be ignored without
warning. If the function terminates with an error when it
is sent an empty data series, the option
stat.safe.mode
should not be set to FALSE
or
trendLevel
may fail. Note: The stat.safe.mode
= TRUE
option returns an NA without warning for empty data
series.openColours
and drawOpenKey
for
more detailed plot control and
openair.generics
for output handling.#basic use
#default statistic = "mean"
trendLevel(mydata, pollutant = "nox")
#applying same as 'own' statistic
my.mean <- function(x) mean(x, na.rm = TRUE)
trendLevel(mydata, pollutant = "nox", statistic = my.mean)
#alternative for 'third party' statistic
#trendLevel(mydata, pollutant = "nox", statistic = mean,
# stat.args = list(na.rm = TRUE))
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