shared_openair_params: Shared openair parameters

In openair: Tools for the Analysis of Air Pollution Data

Shared openair parameters

Description

This is a central place for describing common shared parameters. This ensures consistency across openair

Arguments

ws	The name of the column in mydata representing the wind speed. Defaults to "ws".
wd	The name of the column in mydata representing the decimal wind direction, 0 to 360 where 0/360 are North and 180 is South. Defaults to "wd".
type	Character string(s) defining how data should be split/conditioned before plotting. "default" produces a single panel using the entire dataset. Any other options will split the plot into different panels - a roughly square grid of panels if one type is given, or a 2D matrix of panels if two types are given. type is always passed to cutData(), and can therefore be any of: A built-in type defined in cutData() (e.g., "season", "year", "weekday", etc.). For example, type = "season" will split the plot into four panels, one for each season. The name of a numeric column in mydata, which will be split into n.levels quantiles (defaulting to 4). The name of a character or factor column in mydata, which will be used as-is. Commonly this could be a variable like "site" to ensure data from different monitoring sites are handled and presented separately. It could equally be any arbitrary column created by the user (e.g., whether a nearby possible pollutant source is active or not). Most openair plotting functions can take two type arguments. If two are given, the first is used for the columns and the second for the rows.
cols	Colours to use for plotting. Can be a pre-set palette (e.g., "turbo", "viridis", "tol", "Dark2", etc.) or a user-defined vector of R colours (e.g., c("yellow", "green", "blue", "black") - see colours() for a full list) or hex-codes (e.g., c("#30123B", "#9CF649", "#7A0403")). Alternatively, can be a list of arguments to control the colour palette more closely (e.g., palette, direction, alpha, etc.). See openColours() and colourOpts() for more details.
date.breaks	Number of major x-axis intervals to use. The function will try and choose a sensible number of dates/times as well as formatting the date/time appropriately to the range being considered. The user can override this behaviour by adjusting the value of date.breaks up or down.
date.format	This option controls the date format on the x-axis. A sensible format is chosen by default, but the user can set date.format to override this. For format types see strptime(). For example, to format the date like "Jan-2012" set date.format = "\%b-\%Y".
breaks	breaks bins a continuous axis into discrete bins. It can either take a single number (e.g., breaks = 5) to split the scale into quantiles, a vector of numbers (e.g., ⁠breaks = c(0, 50, 100, 200, 500⁠) to define specific break-points, or a named list. See breakOpts() for more details.
ref.x	Either a single value or values representing the x axis intercepts to draw lines, or a list such as that provided by refOpts() to customise the colour/width/type/etc. of each line. See refOpts() for more details.
ref.y	Either a single value or values representing the y axis intercepts to draw lines, or a list such as that provided by refOpts() to customise the colour/width/type/etc. of each line. See refOpts() for more details.
angle.scale	In radial plots (e.g., polarPlot()), the radial scale is drawn directly on the plot itself. While suitable defaults have been chosen, sometimes the placement of the scale may interfere with an interesting feature. angle.scale can take any value between 0 and 360 to place the scale at a different angle, or FALSE to move it to the side of the plots.
windflow	If TRUE, the vector-averaged wind speed and direction will be plotted using arrows. Alternatively, can be a list of arguments to control the appearance of the arrows (colour, linewidth, alpha value, etc.). See windflowOpts() for details.
offset	offset controls the size of the 'hole' in the middle and is expressed on a scale of 0 to 100, where 0 is no hole and 100 is a hole that takes up the entire plotting area.
limits	The limits of the colour scale, in the form c(lower, upper). For example, limits = c(0, 100) will set the colour scale to be between 0 and 100. Values greater than 100 will be coloured as if they were 100, and those lower than 0 will be coloured as if they were 0. limits can be wider than the range of the data, which can be useful for ensuring multiple plots share the same colour scale.
trans	Should a transformation be applied to the colour scale? If the distribution of data is skewed, the default scale may be dominated by a few high values, so a log or square-root transform may mean the whole colour scale is better presented on the plot. Can be: FALSE, which performs no transform. TRUE, which uses an appropriate transform for the plot type (usually "log10"). A scales 'transform' object (e.g., scales::transform_log10()). A character string corresponding to a scales transform function. Useful options include "sqrt", "log10", "log2", "log1p", "pseudo_log" and "reverse".
key.position	Location where the legend is to be placed. Allowed arguments include "top", "right", "bottom", "left" and "none", the last of which removes the legend entirely.
key.title	Used to set the title of the legend. The legend title is passed to quickText() if auto.text = TRUE.
key.columns	Number of columns to be used in a categorical legend. With many categories a single column can make to key too wide. The user can thus choose to use several columns by setting key.columns to be less than the number of categories.
auto.text	Either TRUE (default) or FALSE. If TRUE titles and axis labels will automatically try and format pollutant names and units properly, e.g., by subscripting the "2" in "NO2". Passed to quickText().
plot	When openair plots are created they are automatically printed to the active graphics device. plot = FALSE deactivates this behaviour. This may be useful when the plot data is of more interest, or the plot is required to appear later (e.g., later in a Quarto document, or to be saved to a file).
key	Deprecated; please use key.position. If FALSE, sets key.position to "none".
...	Addition options are passed on to cutData() for type handling. Some additional arguments are also available, varying somewhat in different plotting functions: title, subtitle, caption, tag, xlab and ylab control the plot title, subtitle, caption, tag, x-axis label and y-axis label, passed to ggplot2::labs() via quickText() if auto.text = TRUE. xlim, ylim and limits control the limits of the x-axis, y-axis and colorbar scales. ncol and nrow set the number of columns and rows in a faceted plot. scales can be "fixed", "free_x", "free_y" or "free" to control whether axes are shared across facets when using type. Also supported are the legacy x.relation and y.relation, which can be either "same" or "free" and get remapped to scales automatically. Similarly, space, axes, axis.labels, switch and strip.position can be used to customise the appearance of faceted plots. See ggplot2::facet_wrap() and ggplot2::facet_grid() for the arguments these take. fontsize overrides the overall font size of the plot by setting the text argument of ggplot2::theme(). It may also be applied proportionately to any openair annotations (e.g., N/E/S/W labels on polar coordinate plots). Various graphical parameters are also supported: linewidth, linetype, shape, size, border, and alpha. Not all parameters apply to all plots. These can take a single value, or a vector of multiple values - e.g., shape = c(1, 2) - which will be recycled to the length of values needed. lineend, linejoin and linemitre tweak the appearance of line plots; see ggplot2::geom_line() for more information. In polar coordinate plots, annotate = FALSE will remove the N/E/S/W labels and any other annotations.

openair documentation built on May 20, 2026, 5:07 p.m.