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Map layer: polygons

Source: R/tm_layers_polygons.R
tm_polygons.Rd

Map layer that draws polygons. Supported visual variables are: fill (the fill color), col (the border color), lwd (line width), lty (line type), fill_alpha (fill color alpha transparency) and col_alpha (border color alpha transparency).

The family of opt_*() functions can be used to specify options in the different tm_*() functions.

Usage

tm_polygons(
  fill = tm_const(),
  fill.scale = tm_scale(),
  fill.legend = tm_legend(),
  fill.chart = tm_chart_none(),
  fill.free = NA,
  col = tm_const(),
  col.scale = tm_scale(),
  col.legend = tm_legend(),
  col.chart = tm_chart_none(),
  col.free = NA,
  lwd = tm_const(),
  lwd.scale = tm_scale(),
  lwd.legend = tm_legend(),
  lwd.chart = tm_chart_none(),
  lwd.free = NA,
  lty = tm_const(),
  lty.scale = tm_scale(),
  lty.legend = tm_legend(),
  lty.chart = tm_chart_none(),
  lty.free = NA,
  fill_alpha = tm_const(),
  fill_alpha.scale = tm_scale(),
  fill_alpha.legend = tm_legend(),
  fill_alpha.chart = tm_chart_none(),
  fill_alpha.free = NA,
  col_alpha = tm_const(),
  col_alpha.scale = tm_scale(),
  col_alpha.legend = tm_legend(),
  col_alpha.chart = tm_chart_none(),
  col_alpha.free = NA,
  linejoin = "round",
  lineend = "round",
  plot.order = tm_plot_order("lwd", reverse = TRUE, na.order = "bottom"),
  zindex = NA,
  group = NA,
  group.control = "check",
  popup.vars = NA,
  popup.format = list(),
  hover = NA,
  id = "",
  options = opt_tm_polygons(),
  ...
)

tm_fill(...)

tm_borders(col = tm_const(), ...)

opt_tm_polygons(polygons.only = "ifany")

Arguments

fill, fill.scale, fill.legend, fill.chart, fill.free

Visual variable that determines the fill color. See details.

col, col.scale, col.legend, col.chart, col.free

Visual variable that determines the color. See details.

lwd, lwd.scale, lwd.legend, lwd.chart, lwd.free

Visual variable that determines the line width. See details.

lty, lty.scale, lty.legend, lty.chart, lty.free

Visual variable that determines the line type. See details.

fill_alpha, fill_alpha.scale, fill_alpha.chart, fill_alpha.legend, fill_alpha.free

Visual variable that determines the fill color transparency. See details.

col_alpha, col_alpha.scale, col_alpha.legend, col_alpha.chart, col_alpha.free

Visual variable that determines the color transparency. See details.

linejoin, lineend

Line join and line end. See gpar() for details.

plot.order

Specification in which order the spatial features are drawn. See tm_plot_order() for details.

zindex

Map layers are drawn on top of each other. The zindex numbers (one for each map layer) determines the stacking order. By default the map layers are drawn in the order they are called.

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).

popup.vars

names of data variables that are shown in the popups in "view" mode. Set popup.vars to TRUE to show all variables in the shape object. Set popup.vars to FALSE to disable popups. Set popup.vars to a character vector of variable names to those those variables in the popups. The default (NA) depends on whether visual variables (e.g.fill) are used. If so, only those are shown. If not all variables in the shape object are shown.

popup.format

list of formatting options for the popup values. See the argument legend.format for options. Only applicable for numeric data variables. If one list of formatting options is provided, it is applied to all numeric variables of popup.vars. Also, a (named) list of lists can be provided. In that case, each list of formatting options is applied to the named variable.

hover

name of the data variable that specifies the hover labels (view mode only). Set to FALSE to disable hover labels. By default FALSE, unless id is specified. In that case, it is set to id,

id

name of the data variable that specifies the indices of the spatial features. Only used for "view" mode.

options

options passed on to the corresponding opt_<layer_function> function

...

to catch deprecated arguments from version < 4.0

polygons.only

should only polygon geometries of the shape object (defined in tm_shape()) be plotted? By default "ifany", which means TRUE in case a geometry collection is specified.

Details

The visual variable arguments (e.g. col) can be specified with either a data variable name (e.g., a spatial vector attribute or a raster layer of the object specified in tm_shape()), or with a visual value (for col, a color is expected). Multiple values can be specified: in that case facets are created. These facets can be combined with other faceting data variables, specified with tm_facets().

  • The *.scale arguments determine the used scale to map the data values to visual variable values. These can be specified with one of the available tm_scale_*() functions. The default is specified by the tmap option (tm_options()) scales.var.

  • The *.legend arguments determine the used legend, specified with tm_legend(). The default legend and its settings are determined by the tmap options (tm_options()) legend. .

  • The *.chart arguments specify additional charts, specified with tm_chart_, e.g. tm_chart_histogram()

  • The *.free arguments determine whether scales are applied freely across facets, or shared. A logical value is required. They can also be specified with a vector of three logical values; these determine whether scales are applied freely per facet dimension. This is only useful when facets are applied (see tm_facets()). There are maximally three facet dimensions: rows, columns, and pages. This only applies for a facet grid (tm_facets_grid()). For instance, col.free = c(TRUE, FALSE, FALSE) means that for the visual variable col, each row of facets will have its own scale, and therefore its own legend. For facet wraps and stacks (tm_facets_wrap() and tm_facets_stack()) there is only one facet dimension, so the *.free argument requires only one logical value.

Examples

# load Africa country data
data(World)
Africa = World[World$continent == "Africa", ]
Africa_border = sf::st_make_valid(sf::st_union(sf::st_buffer(Africa, 0.001))) # slow and ugly

# without specifications
tm_shape(Africa_border) + tm_polygons()

tm_shape(Africa_border) + tm_fill()

tm_shape(Africa_border) + tm_borders()


# specification with visual variable values
tm_shape(Africa) +
  tm_polygons(fill = "limegreen", col = "purple", lwd = 2, lty = "solid", col_alpha = 0.3) +
  tm_text("name", options = opt_tm_text(remove_overlap = TRUE)) +
tm_shape(Africa_border) +
  tm_borders("darkred", lwd = 3)


# specification with a data variable
tm_shape(Africa) +
  tm_polygons(fill = "income_grp", fill.scale = tm_scale_categorical(values = "-tol.muted"))



# continuous color scale with landscape legend
tm_shape(Africa) +
  tm_polygons(fill = "inequality",
    fill.scale = tm_scale_continuous(values = "-scico.roma"),
    fill.legend = tm_legend(
      title = "", orientation = "landscape",
      position = tm_pos_out("center", "bottom"), frame = FALSE
      )) +
tm_shape(Africa_border) +
  tm_borders(lwd = 2) +
tm_title("Inequality index", position = tm_pos_in("right", "TOP"), frame = FALSE) +
tm_layout(frame = FALSE)


# bivariate scale
tm_shape(World) +
  tm_polygons(tm_vars(c("inequality", "well_being"), multivariate = TRUE))
#> Labels abbreviated by the first letters, e.g.: "2 to 3" => "2"

tm_shape(World) +
  tm_polygons(

   )