tmap (version 1.6)

tm_scale_bar: Scale bar

Description

Creates a scale bar. By default, the coordinate units are assumed to be meters, and the map units in kilometers. This can be changed in tm_shape.

Usage

tm_scale_bar(breaks = NULL, width = 0.25, size = 0.5, text.color = NA, color.dark = "black", color.light = "white", lwd = 1, position = NA, just = NA)

Arguments

breaks

breaks of the scale bar. If not specified, breaks will be automatically be chosen given the prefered width of the scale bar.

width

(prefered) width of the scale bar. Only applicable when breaks=N ULL

size

relative text size (which is upperbound by the available label width)

text.color

color of the text. By default equal to the argument attr.color of tm_layout.

color.dark

color of the dark parts of the scale bar, typically (and by default) black.

color.light

color of the light parts of the scale bar, typically (and by default) white.

lwd

line width of the scale bar

position

position of the scale bar Vector of two values, specifing the x and y coordinates. Either this vector contains "left", "LEFT", "center", "right", or "RIGHT" for the first value and "top", "TOP", "center", "bottom", or "BOTTOM" for the second value, or this vector contains two numeric values between 0 and 1 that specifies the x and y value of the left bottom corner of the scale bar. The uppercase values correspond to the position without margins (so tighter to the frame). The default value is controlled by the argument "attr.position" of tm_layout.

just

Justification of the attribute relative to the point coordinates. The first value specifies horizontal and the second value vertical justification. Possible values are: "left" , "right", "center", "bottom", and "top". Numeric values of 0 specify left/bottom alignment and 1 right/top alignment. This option is only used, if position is specified by numeric coordinates. The default value is controlled by the argument "attr.just" of tm_layout.

Examples

current.mode <- tmap_mode("plot")

data(NLD_muni)
qtm(NLD_muni, theme = "NLD") + tm_scale_bar(position=c("left", "bottom"))

data(Europe)
tm_shape(Europe, unit = "miles", unit.size=1609) + 
	tm_polygons() + 
tm_scale_bar()  + tm_layout(attr.outside = TRUE)

# restore current mode
tmap_mode(current.mode)