scalebar: scalebar

In ggsn: North Symbols and Scale Bars for Maps Created with 'ggplot2' or 'ggmap'

Description

Adds a scale bar to maps created with ggplot or ggmap.

Usage

scalebar(data = NULL, location = "bottomright", dist = NULL,
  dist_unit = NULL, transform = NULL, dd2km = NULL, model = NULL,
  height = 0.02, st.dist = 0.02, st.bottom = TRUE, st.size = 5,
  st.color = "black", box.fill = c("black", "white"),
  box.color = "black", border.size = 1, x.min = NULL, x.max = NULL,
  y.min = NULL, y.max = NULL, anchor = NULL, facet.var = NULL,
  facet.lev = NULL, ...)

Arguments

data	the same data.frame passed to ggplot to plot the map.
location	string indicating the scale bar's location in the plot. Possible options: "topright" (default), "bottomright", "bottomleft" and "topleft".
dist	distance to represent with each segment of the scale bar.
dist_unit	unit of measurement for dist. Possbile values: "km" (kilometers) and "m" (meters), "nm" (nautical miles) and "mi" (statue miles).
transform	If TRUE, it is assumed that coordinates are in decimal degrees. If FALSE, it assumed that they are in meters.
dd2km	deprecated. Use transform instead.
model	choice of ellipsoid model ("WGS84", "GRS80", "Airy", "International", "Clarke", or "GRS67") Used when transform is TRUE.
height	number between 0 and 1 to indicate the scale bar's height, as a proportion of the y axis.
st.dist	number between 0 and 1 to indicate the distance between the scale bar and the scale bar's text, as a proportion of the y axis.
st.bottom	logical. If TRUE (default) the scale bar's text is displayed at the bottom of the scale bar, if FALSE, it is displayed at the top.
st.size	number to indicate the scale bar's size. It is passed to size in annotate function.
st.color	color of the scale bar's text. Default is black.
box.fill	fill color of the box. If vector of two colors, the two boxes are filled with a different color. Defaults to black and white.
box.color	color of the box's border. If vector of two colors, the borders of the two boxes are colored differently. Defaults to black.
border.size	number to define the border size.
x.min	if data is not defined, number with the minimum x coordinate. Useful for ggmap.
x.max	if data is not defined, number with the maximum x coordinate. Useful for ggmap.
y.min	if data is not defined, number with the minimum y coordinate. Useful for ggmap.
y.max	if data is not defined, number with the maximum y coordinate. Useful for ggmap.
anchor	named vector with coordinates to control the symbol's position. For location = "topright", anchor defines the coordinates of the symbol's topright corner and so forth. The x coordinate must be named as x and the y coordinate as y.
facet.var	if faceting, character vector of variable names used for faceting. This is useful for placing the scalebar in only one facet and must be used together with facet.lev.
facet.lev	character vector with the name of one level for each variable in facet.var. The scale bar will be drawn only in the facet.lev facet.
...	further arguments passed to geom_text.

Examples

## Not run: 
library(sf)
data(domestic_violence)

# Map in geographic coordinates
ggplot(domestic_violence, aes(fill = Scaled)) +
    geom_sf() +
    scalebar(domestic_violence, dist = 4, dist_unit = "km",
             transform = TRUE, model = "WGS84") +
    blank() +
    scale_fill_continuous(low = "#fff7ec", high = "#7F0000")

# Map in projected coordinates
domestic_violence2 <- st_transform(domestic_violence, 31983)
ggplot(domestic_violence2, aes(fill = Scaled)) +
    geom_sf() +
    scalebar(domestic_violence2, dist = 4, dist_unit = "km",
             transform = FALSE, model = "WGS84") +
    blank() +
    scale_fill_continuous(low = "#fff7ec", high = "#7F0000")

## End(Not run)

Example output

Loading required package: ggplot2
Loading required package: grid
Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1

ggsn documentation built on May 1, 2019, 8:21 p.m.