# tm_grid

From tmap v1.11
0th

Percentile

##### Coordinate grid lines

Creates a tmap-element that draws coordinate grid lines. It serves as a layer that can be drawn anywhere between other layers. By default the coordinate system of the (master) shape object is used, which results in horizontal and vertical lines. Alternatively, grid lines can be reprojected, for instance to latitude longitude coordinates, and hence be curved.

##### Usage
tm_grid(x = NA, y = NA, n.x = NA, n.y = NA, projection = NA,
col = NA, lwd = 1, alpha = NA, labels.size = 0.6, labels.col = NA,
labels.rot = c(0, 0), labels.format = list(big.mark = ","),
labels.margin.x = 0, labels.margin.y = 0, labels.inside.frame = TRUE)
##### Arguments
x

x coordinates for vertical grid lines. If NA, it is specified with a pretty scale and n.x.

y

y coordinates for horizontal grid lines. If NA, it is specified with a pretty scale and n.y.

n.x

prefered number of grid lines for the x axis.

n.y

prefered number of grid lines for the y axis.

projection

projection character. If specified, the grid lines are projected accordingly. See set_projection for projection details. Many world maps are projected, but still have latitude longitude ("longlat") grid lines.

col

color of the grid lines.

lwd

line width of the grid lines

alpha

alpha transparency of the grid lines. Number between 0 and 1. By default, the alpha transparency of col is taken.

labels.size

font size of the tick labels

labels.col

font color of the tick labels

labels.rot

Rotation angles of the labels. Vector of two values: the first is the rotation angle (in degrees) of the tick labels on the x axis and the second is the rotation angle of the tick labels on the y axis. Only 0, 90, 180, and 270 are valid values.

labels.format

list of formatting options for the grid labels. Parameters are:

fun

Function to specify the labels. It should take a numeric vector, and should return a character vector of the same size. By default it is not specified. If specified, the list items scientific, format, and digits (see below) are not used.

scientific

Should the labels be formatted scientically? If so, square brackets are used, and the format of the numbers is "g". Otherwise, format="f", and text.separator, text.less.than, and text.or.more are used. Also, the numbers are automatically rounded to millions or billions if applicable.

format

By default, "f", i.e. the standard notation xxx.xxx, is used. If scientific=TRUE then "g", which means that numbers are formatted scientically, i.e. n.dddE+nn if needed to save space.

digits

Number of digits after the decimal point if format="f", and the number of significant digits otherwise.

...

Other arguments passed on to formatC

labels.margin.x

margin between tick labels of x axis and the frame

labels.margin.y

margin between tick labels of y axis and the frame

labels.inside.frame

Show labels inside the frame?

##### Aliases
• tm_grid
Documentation reproduced from package tmap, version 1.11, License: GPL-3

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