Percentile roses on a static ggmap

pollroseMapStatic() creates a ggplot2 map using percentile roses as markers. As this function returns a ggplot2 object, further customisation can be achieved using functions like ggplot2::theme() and ggplot2::guides().

Usage

pollroseMapStatic(
  data,
  pollutant = NULL,
  ggmap,
  statistic = "prop.count",
  breaks = NULL,
  facet = NULL,
  latitude = NULL,
  longitude = NULL,
  cols = "turbo",
  alpha = 1,
  key = FALSE,
  facet.nrow = NULL,
  d.icon = 150,
  d.fig = 3,
  ...
)

Arguments

data

A data frame. The data frame must contain the data to plot the directional analysis marker, which includes wind speed (ws), wind direction (wd), and the column representing the concentration of a pollutant. In addition, data must include a decimal latitude and longitude.

pollutant

The column name(s) of the pollutant(s) to plot. If multiple pollutants are specified, they will each form part of a separate panel.

ggmap

A ggmap object obtained using ggmap::get_map() or a similar function to use as the basemap.

statistic

The statistic to be applied to each data bin in the plot. Options currently include "prop.count", "prop.mean" and "abs.count". The default "prop.count" sizes bins according to the proportion of the frequency of measurements. Similarly, "prop.mean" sizes bins according to their relative contribution to the mean. "abs.count" provides the absolute count of measurements in each bin.

breaks

Most commonly, the number of break points. If not specified, each marker will independently break its supplied data at approximately 6 sensible break points. When breaks are specified, all markers will use the same break points. Breaks can also be used to set specific break points. For example, the argument breaks = c(0, 1, 10, 100) breaks the data into segments <1, 1-10, 10-100, >100.

facet

Used for splitting the input data into different panels, passed to the type argument of openair::cutData(). facet cannot be used if multiple pollutant columns have been provided.

latitude, longitude

The decimal latitude/longitude. If not provided, will be automatically inferred from data by looking for a column named "lat"/"latitude" or "lon"/"lng"/"long"/"longitude" (case-insensitively).

cols

The colours used for plotting. See openair::openColours() for more information.

alpha

The alpha transparency to use for the plotting surface (a value between 0 and 1 with zero being fully transparent and 1 fully opaque).

key

Should a key for each marker be drawn? Default is FALSE.

facet.nrow

Passed to the nrow argument of ggplot2::facet_wrap().

d.icon

The diameter of the plot on the map in pixels. This will affect the size of the individual polar markers. Alternatively, a vector in the form c(width, height) can be provided if a non-circular marker is desired.

d.fig

The diameter of the plots to be produced using openair in inches. This will affect the resolution of the markers on the map. Alternatively, a vector in the form c(width, height) can be provided if a non-circular marker is desired.

...

Arguments passed on to openair::pollutionRose

key.footer

Adds additional text/labels below the scale key. See key.header for further information.

key.position

Location where the scale key is to plotted. Allowed arguments currently include “top”, “right”, “bottom” and “left”.

paddle

Either TRUE or FALSE. If TRUE plots rose using 'paddle' style spokes. If FALSE plots rose using 'wedge' style spokes.

seg

When paddle = TRUE, seg determines with width of the segments. For example, seg = 0.5 will produce segments 0.5 * angle.

normalise

If TRUE each wind direction segment is normalised to equal one. This is useful for showing how the concentrations (or other parameters) contribute to each wind sector when the proportion of time the wind is from that direction is low. A line showing the probability that the wind directions is from a particular wind sector is also shown.

Value

a ggplot2 plot with a ggmap basemap

Further customisation using ggplot2

As the outputs of the static directional analysis functions are ggplot2 figures, further customisation is possible using functions such as ggplot2::theme(), ggplot2::guides() and ggplot2::labs().

If multiple pollutants are specified, subscripting (e.g., the "x" in "NOx") is achieved using the ggtext package. Therefore if you choose to override the plot theme, it is recommended to use [ggplot2::theme()] and [ggtext::element_markdown()] to define the strip.text parameter.

When arguments like limits, percentile or breaks are defined, a legend is automatically added to the figure. Legends can be removed using ggplot2::theme(legend.position = "none"), or further customised using ggplot2::guides() and either color = ggplot2::guide_colourbar() for continuous legends or fill = ggplot2::guide_legend() for discrete legends.

See also

the original openair::pollutionRose()

pollroseMap() for the interactive leaflet equivalent of pollroseMapStatic()

Other static directional analysis maps: annulusMapStatic(), diffMapStatic(), freqMapStatic(), percentileMapStatic(), polarMapStatic(), windroseMapStatic()