windroseMap: Wind roses on dynamic and static maps

In davidcarslaw/openairmaps: Create Maps of Air Pollution Data

Wind roses on dynamic and static maps

Description

The windroseMap() function creates a map using wind roses as markers. Multiple layers of markers can be created using the type argument. By default, these maps are dynamic and can be panned, zoomed, and otherwise interacted with. Using the static argument allows for static images to be produced instead.

Usage

windroseMap(
  data,
  ws.int = 2,
  breaks = 4,
  latitude = NULL,
  longitude = NULL,
  crs = 4326,
  type = NULL,
  popup = NULL,
  label = NULL,
  provider = "OpenStreetMap",
  cols = "turbo",
  alpha = 1,
  key = FALSE,
  legend = TRUE,
  legend.position = NULL,
  legend.title = NULL,
  legend.title.autotext = TRUE,
  control.collapsed = FALSE,
  control.position = "topright",
  control.autotext = TRUE,
  d.icon = 200,
  d.fig = 3.5,
  static = FALSE,
  static.nrow = NULL,
  ...
)

Arguments

data	Input data table with wind and geo-spatial information. required | scope: dynamic & static A data frame. The data frame must contain the data to plot the directional analysis marker, which includes wind speed (ws) and wind direction (wd). In addition, data must include a decimal latitude and longitude (or X/Y coordinate used in conjunction with crs).
ws.int	The wind speed interval of the colour axis. default: 2 | scope: dynamic & static The wind speed interval. Default is 2 m/s but for low met masts with low mean wind speeds a value of 1 or 0.5 m/s may be better.
breaks	Specifier for the number of breaks of the colour axis. default: 4 | scope: dynamic & static Most commonly, the number of break points for wind speed in openair::windRose(). For the ws.int default of 2, the default breaks, 4, generates the break points 2, 4, 6, and 8. 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.
latitude, longitude	The decimal latitude(Y)/longitude(X). default: NULL | scope: dynamic & static Column names representing the decimal latitude and longitude (or other Y/X coordinate if using a different crs). If not provided, will be automatically inferred from data by looking for a column named "lat"/"latitude" or "lon"/"lng"/"long"/"longitude" (case-insensitively).
crs	The coordinate reference system (CRS). default: 4326 | scope: dynamic & static The coordinate reference system (CRS) of the data, passed to sf::st_crs(). By default this is EPSG:4326, the CRS associated with the commonly used latitude and longitude coordinates. Different coordinate systems can be specified using crs (e.g., crs = 27700 for the British National Grid). Note that non-lat/lng coordinate systems will be re-projected to EPSG:4326 for plotting on the map.
type	A method to condition the data for separate plotting. default: NULL | scope: dynamic & static Used for splitting the input data into different groups, passed to the type argument of openair::cutData(). When type is specified: Dynamic: The different data splits can be toggled between using a "layer control" menu. Static:: The data splits will each appear in a different panel. type cannot be used if multiple pollutant columns have been provided.
popup	Content for marker popups on dynamic maps. default: NULL | scope: dynamic Columns to be used as the HTML content for marker popups on dynamic maps. Popups may be useful to show information about the individual sites (e.g., site names, codes, types, etc.). If a vector of column names are provided they are passed to buildPopup() using its default values.
label	Content for marker hover-over on dynamic maps. default: NULL | scope: dynamic Column to be used as the HTML content for hover-over labels. Labels are useful for the same reasons as popups, though are typically shorter.
provider	The basemap(s) to be used. default: "OpenStreetMap" | scope: dynamic & static The base map(s) to be used beneath the polar markers. If not provided, will default to "OpenStreetMap"/"osm" for both dynamic and static maps. Dynamic: Any number of leaflet::providers. See http://leaflet-extras.github.io/leaflet-providers/preview/ for a list of all base maps that can be used. If multiple base maps are provided, they can be toggled between using a "layer control" interface. By default, the interface will use the provider names as labels, but users can define their own using a named vector (e.g., c("Default" = "OpenStreetMap", "Satellite" = "Esri.WorldImagery")) Static: One of rosm::osm.types(). There is some overlap in static and dynamic providers. For example, {ggspatial} uses "osm" to specify "OpenStreetMap". When static providers are provided to dynamic maps or vice versa, {openairmaps} will attempt to substitute the correct provider string.
cols	Colours to use for plotting. default: "turbo" | scope: dynamic & static The colours used for plotting, passed to openair::openColours(). The default, "turbo", is a rainbow palette with relatively perceptually uniform colours. Read more about this palette at https://research.google/blog/turbo-an-improved-rainbow-colormap-for-visualization/.
alpha	Transparency value for polar markers. default: 1 | scope: dynamic & static A value between 0 (fully transparent) and 1 (fully opaque).
key	Transparency value for polar markers. default: FALSE | scope: dynamic & static Draw a key for each individual marker? Potentially useful when limits = "free", but of limited use otherwise.
legend	Draw a shared legend? default: TRUE | scope: dynamic & static When all markers share the same colour scale (e.g., when limits != "free" in polarMap()), should a shared legend be created at the side of the map?
legend.position	Position of the shared legend. default: NULL | scope: dynamic & static When legend = TRUE, where should the legend be placed? Dynamic: One of "topright", "topright", "bottomleft" or "bottomright". Passed to the position argument of leaflet::addLegend(). Static:: One of "top", "right", "bottom" or "left". Passed to the legend.position argument of ggplot2::theme().
legend.title	Title of the legend. default: NULL | scope: dynamic & static By default, when legend.title = NULL, the function will attempt to provide a sensible legend title. legend.title allows users to overwrite this - for example, to include units or other contextual information. For dynamic maps, users may wish to use HTML tags to format the title.
legend.title.autotext	Automatically format the title of the legend? default: TRUE | scope: dynamic & static When legend.title.autotext = TRUE, legend.title will be first run through quickTextHTML() (dynamic) or openair::quickText() (static).
control.collapsed	Show the layer control as a collapsed? default: FALSE | scope: dynamic For dynamic maps, should the "layer control" interface be collapsed? If TRUE, users will have to hover over an icon to view the options.
control.position	Position of the layer control menu default: "topright" | scope: dynamic When type != NULL, or multiple pollutants are specified, where should the "layer control" interface be placed? One of "topleft", "topright", "bottomleft" or "bottomright". Passed to the position argument of leaflet::addLayersControl().
control.autotext	Automatically format the content of the layer control menu? default: TRUE | scope: dynamic When control.autotext = TRUE, the content of the "layer control" interface will be first run through quickTextHTML().
d.icon	The diameter of the plot on the map in pixels. default: 200 | scope: dynamic & static 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. default: 3.5 | scope: dynamic & static 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.
static	Produce a static map? default: FALSE This controls whether a dynamic or static map is produced. The former is the default and is broadly more useful, but the latter may be preferable for DOCX or PDF outputs (e.g., academic papers).
static.nrow	Number of rows in a static map. default: NULL | scope: static Controls the number of rows of panels on a static map when multiple pollutants or type are specified; passed to the nrow argument of ggplot2::facet_wrap(). The default, NULL, results in a roughly square grid of panels.
...	Arguments passed on to openair::windRose ws Name of the column representing wind speed. wd Name of the column representing wind direction. ws2,wd2 The user can supply a second set of wind speed and wind direction values with which the first can be compared. See pollutionRose() for more details. angle Default angle of “spokes” is 30. Other potentially useful angles are 45 and 10. Note that the width of the wind speed interval may need adjusting using width. bias.corr When angle does not divide exactly into 360 a bias is introduced in the frequencies when the wind direction is already supplied rounded to the nearest 10 degrees, as is often the case. For example, if angle = 22.5, N, E, S, W will include 3 wind sectors and all other angles will be two. A bias correction can made to correct for this problem. A simple method according to Applequist (2012) is used to adjust the frequencies. grid.line Grid line interval to use. If NULL, as in default, this is assigned based on the available data range. However, it can also be forced to a specific value, e.g. grid.line = 10. grid.line can also be a list to control the interval, line type and colour. For example grid.line = list(value = 10, lty = 5, col = "purple"). width For paddle = TRUE, the adjustment factor for width of wind speed intervals. For example, width = 1.5 will make the paddle width 1.5 times wider. seg When paddle = TRUE, seg determines with width of the segments. For example, seg = 0.5 will produce segments 0.5 * angle. 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. offset The size of the 'hole' in the middle of the plot, expressed as a percentage of the polar axis scale, default 10. 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. max.freq Controls the scaling used by setting the maximum value for the radial limits. This is useful to ensure several plots use the same radial limits. paddle Either TRUE or FALSE. If TRUE plots rose using 'paddle' style spokes. If FALSE plots rose using 'wedge' style spokes. key.header Adds additional text/labels above the scale key. For example, passing windRose(mydata, key.header = "ws") adds the addition text as a scale header. Note: This argument is passed to drawOpenKey() via quickText(), applying the auto.text argument, to handle formatting. 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”. dig.lab The number of significant figures at which scientific number formatting is used in break point and key labelling. Default 5. include.lowest Logical. If FALSE (the default), the first interval will be left exclusive and right inclusive. If TRUE, the first interval will be left and right inclusive. Passed to the include.lowest argument of cut(). 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. pollutant Alternative data series to be sampled instead of wind speed. The windRose() default NULL is equivalent to pollutant = "ws". Use in pollutionRose(). angle.scale The scale is by default shown at a 315 degree angle. Sometimes the placement of the scale may interfere with an interesting feature. The user can therefore set angle.scale to another value (between 0 and 360 degrees) to mitigate such problems. For example angle.scale = 45 will draw the scale heading in a NE direction. border Border colour for shaded areas. Default is no border.

Value

Either:

• Dynamic: A leaflet object

• Static: A ggplot2 object using ggplot2::coord_sf() coordinates with a ggspatial basemap

Customisation of static maps 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

openair::windRose()

Other directional analysis maps: annulusMap(), diffMap(), freqMap(), percentileMap(), polarMap(), pollroseMap()

Examples

## Not run: 
windroseMap(polar_data,
  provider = "CartoDB.Voyager"
)

## End(Not run)

davidcarslaw/openairmaps documentation built on April 28, 2024, 3 p.m.