map_ng: Map of Nigeria

In BroVic/naijR: Operations to Ease Data Analyses Specific to Nigeria

Map of Nigeria

Description

Maps of the Federal Republic of Nigeria that are based on the basic plotting idiom utilised by maps:map and its variants.

Usage

map_ng(
  region = character(),
  data = NULL,
  x = NULL,
  y = NULL,
  breaks = NULL,
  categories = NULL,
  excluded = NULL,
  exclude.fill = NULL,
  title = NULL,
  caption = NULL,
  show.neighbours = FALSE,
  show.text = FALSE,
  legend.text = NULL,
  leg.title,
  plot = TRUE,
  ...
)

Arguments

region	A character vector of regions to be displayed. This could be States or Local Government Areas.
data	An object containing data, principally the variables required to plot in a map.
x, y	Numeric object or factor (or coercible to one). See Details.
breaks	Numeric. A vector of length >= 1. If a single value i.e. scalar, it denotes the expected number of breaks. Internally, the function will attempt to compute appropriate category sizes or fail if out-of bounds. Where length is >= 3L, it is expected to be an arithmetic sequence that represents category bounds as for cut (applicable only to choropleth maps).
categories	The legend for the choropleth-plotted categories. If not defined, internally created labels are used.
excluded	Regions to be excluded from a choropleth map.
exclude.fill	Colour-shading to be used to indicate excluded regions. Must be a vector of the same length as excluded.
title, caption	An optional string for annotating the map.
show.neighbours	Logical; TRUE to display the immediate vicinity neighbouring regions/countries.
show.text	Logical. Whether to display the labels of regions.
legend.text	Logical (whether to show the legend) or character vector (actual strings for the legend). The latter will override whatever is provided by categories, giving the user additional control.
leg.title	String. The legend title. If missing, a default value is acquired from the data. To turn off the legend title, pass NULL.
plot	Logical. Turn actual plotting of the map off or on.
...	Further arguments passed to plot

Details

The default value for region is to print all State boundaries. data enables the extraction of data for plotting from an object of class data.frame. Columns containing regions (i.e. States as well as supported sub-national jurisdictions) are identified. The argument also provides context for quasiquotation when providing the x and y arguments.

For x and y, when both arguments are supplied, they are taken to be point coordinates, where x represent longitude and y latitude. If only x is supplied, it is assumed that the intention of the user is to make a choropleth map, and thus, numeric vector arguments are converted into factors i.e. number classes. Otherwise factors or any object that can be coerced to a factor should be used.

For plain plots, the col argument works the same as with map. For choropleth maps, the colour provided represents a (sequential) colour palette based on RColorBrewer::brewer.pal. The available colour options can be checked with getOption("choropleth.colours") and this can also be modified by the user.

If the default legend is unsatisfactory, it is recommended that the user sets the legend.text argument to FALSE; the next function call should be legend which will enable finer control over the legend.

Value

An object of class sf, which is a standard format containing the data used to draw the map and thus can be used by this and other popular R packages to visualize the spatial data.

Note

When adjusting the default colour choices for choropleth maps, it is advisable to use one of the sequential palettes. For a list of of available palettes, especially for more advanced use, review RColorBrewer::display.brewer.all.

See Also

vignette("nigeria-maps") for additional ways to use this function.

Examples

## Not run: 
map_ng() # Draw a map with default settings
map_ng(states("sw"))
map_ng("Kano")
## End(Not run)

BroVic/naijR documentation built on Oct. 15, 2024, 8:38 p.m.