Map component: manual legend

Map component that adds a manual legend.

Usage

tm_add_legend(
  ...,
  labels = "",
  type = "symbols",
  title = "",
  orientation = NULL,
  position = NULL,
  group_id = NA_character_,
  group = NA,
  group.control = "check",
  z = NA_integer_
)

Arguments

...

visual variables and arguments passed on to tm_legend(). By default, the argument type is set to "symbols", which means that the supported visual variables are: "fill", "col", "shape", "size", "fill_alpha", "col_alpha", "lty", "lwd", "linejoin", and "lineend". The number of legend items will be equal to the maximum number of specific values (and specified labels.)

labels

labels by default "" (so omitted)

type

the layer type from which the visual variables (see ...) are taken. Options: "symbols" (default), "lines", "polygons", and "text".

title

The title of the legend.

orientation

The orientation of the legend.

position

The position of the legend. A tm_pos object, or a shortcut of two values: horizontal (left, center, right) and vertical (top, center, bottom). See tm_pos for details

group_id

Component group id name. All components (e.g. legends, titles, etc) with the same group_id will be grouped. The specifications of how they are placed (e.g. stacking, margins etc.) are determined in tm_components() where its argument id should correspond to group_id.

group

Name of the group to which this layer belongs. This is only relevant in view mode, where layer groups can be switched (see group.control)

group.control

In view mode, the group control determines how layer groups can be switched on and off. Options: "radio" for radio buttons (meaning only one group can be shown), "check" for check boxes (so multiple groups can be shown), and "none" for no control (the group cannot be (de)selected).

z

z index, e.g. the place of the component relative to the other componets

Examples

if (FALSE) { # \dontrun{
tm_shape(NLD_muni) +
  tm_borders() +
  tm_basemap("OpenStreetMap") +
  tm_add_legend(labels = c("Motorway", "Primary road", "Secondary road", "Railway"),
          col = c("#E892A1", "#FCD6A4", "#F8FABF", "#707070"),
          lty = c("solid", "solid", "solid", "dotted"),
          lwd = 3,
          type = "lines",
          bg.color = "grey92",
          bg.alpha = 1)
} # }