Map layer: symbols — tm_symbols • tmap

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

Usage

tm_symbols(
  size = tm_const(),
  size.scale = tm_scale(),
  size.legend = tm_legend(),
  size.chart = tm_chart_none(),
  size.free = NA,
  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,
  shape = tm_const(),
  shape.scale = tm_scale(),
  shape.legend = tm_legend(),
  shape.chart = tm_chart_none(),
  shape.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,
  plot.order = tm_plot_order("size"),
  zindex = NA,
  group = NA,
  group.control = "check",
  popup.vars = NA,
  popup.format = list(),
  hover = NA,
  id = "",
  options = opt_tm_symbols(),
  ...
)

tm_dots(
  fill = tm_const(),
  fill.scale = tm_scale(),
  fill.legend = tm_legend(),
  fill.free = NA,
  size = tm_const(),
  size.scale = tm_scale(),
  size.legend = tm_legend(),
  size.free = NA,
  lwd = tm_const(),
  lwd.scale = tm_scale(),
  lwd.legend = tm_legend(),
  lwd.free = NA,
  lty = tm_const(),
  lty.scale = tm_scale(),
  lty.legend = tm_legend(),
  lty.free = NA,
  fill_alpha = tm_const(),
  fill_alpha.scale = tm_scale(),
  fill_alpha.legend = tm_legend(),
  fill_alpha.free = NA,
  plot.order = tm_plot_order("DATA"),
  zindex = NA,
  group = NA,
  group.control = "check",
  options = opt_tm_dots(),
  ...
)

tm_bubbles(
  size = tm_const(),
  size.scale = tm_scale(),
  size.legend = tm_legend(),
  size.free = NA,
  fill = tm_const(),
  fill.scale = tm_scale(),
  fill.legend = tm_legend(),
  fill.free = NA,
  col = tm_const(),
  col.scale = tm_scale(),
  col.legend = tm_legend(),
  col.free = NA,
  lwd = tm_const(),
  lwd.scale = tm_scale(),
  lwd.legend = tm_legend(),
  lwd.free = NA,
  lty = tm_const(),
  lty.scale = tm_scale(),
  lty.legend = tm_legend(),
  lty.free = NA,
  fill_alpha = tm_const(),
  fill_alpha.scale = tm_scale(),
  fill_alpha.legend = tm_legend(),
  fill_alpha.free = NA,
  col_alpha = tm_const(),
  col_alpha.scale = tm_scale(),
  col_alpha.legend = tm_legend(),
  col_alpha.free = NA,
  plot.order = tm_plot_order("size"),
  zindex = NA,
  group = NA,
  group.control = "check",
  options = opt_tm_bubbles(),
  ...
)

tm_squares(
  size = tm_const(),
  size.scale = tm_scale(),
  size.legend = tm_legend(),
  size.free = NA,
  fill = tm_const(),
  fill.scale = tm_scale(),
  fill.legend = tm_legend(),
  fill.free = NA,
  col = tm_const(),
  col.scale = tm_scale(),
  col.legend = tm_legend(),
  col.free = NA,
  lwd = tm_const(),
  lwd.scale = tm_scale(),
  lwd.legend = tm_legend(),
  lwd.free = NA,
  lty = tm_const(),
  lty.scale = tm_scale(),
  lty.legend = tm_legend(),
  lty.free = NA,
  fill_alpha = tm_const(),
  fill_alpha.scale = tm_scale(),
  fill_alpha.legend = tm_legend(),
  fill_alpha.free = NA,
  col_alpha = tm_const(),
  col_alpha.scale = tm_scale(),
  col_alpha.legend = tm_legend(),
  col_alpha.free = NA,
  plot.order = tm_plot_order("size"),
  zindex = NA,
  group = NA,
  group.control = "check",
  options = opt_tm_squares(),
  ...
)

tm_markers(
  text = tm_const(),
  text.scale = tm_scale(),
  text.legend = tm_legend(),
  text.chart = tm_chart_none(),
  text.free = NA,
  size = tm_const(),
  size.scale = tm_scale(),
  size.legend = tm_legend(),
  size.chart = tm_chart_none(),
  size.free = NA,
  col = tm_const(),
  col.scale = tm_scale(),
  col.legend = tm_legend(),
  col.chart = tm_chart_none(),
  col.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,
  fontface = tm_const(),
  fontface.scale = tm_scale(),
  fontface.legend = tm_legend(),
  fontface.chart = tm_chart_none(),
  fontface.free = NA,
  fontfamily = "",
  bgcol = tm_const(),
  bgcol.scale = tm_scale(),
  bgcol.legend = tm_legend(),
  bgcol.chart = tm_chart_none(),
  bgcol.free = NA,
  bgcol_alpha = tm_const(),
  bgcol_alpha.scale = tm_scale(),
  bgcol_alpha.legend = tm_legend(),
  bgcol_alpha.chart = tm_chart_none(),
  bgcol_alpha.free = NA,
  xmod = 0,
  xmod.scale = tm_scale(),
  xmod.legend = tm_legend_hide(),
  xmod.chart = tm_chart_none(),
  xmod.free = NA,
  ymod = 0,
  ymod.scale = tm_scale(),
  ymod.legend = tm_legend_hide(),
  ymod.chart = tm_chart_none(),
  ymod.free = NA,
  angle = 0,
  angle.scale = tm_scale(),
  angle.legend = tm_legend_hide(),
  angle.chart = tm_chart_none(),
  angle.free = NA,
  plot.order = tm_plot_order("AREA", reverse = FALSE, na.order = "bottom"),
  zindex = NA,
  group = NA,
  group.control = "check",
  options = opt_tm_markers(),
  ...
)

opt_tm_markers(
  markers_on_top_of_text = FALSE,
  points_only = "ifany",
  point_per = "feature",
  on_surface = FALSE,
  shadow = FALSE,
  shadow.offset.x = 0.1,
  shadow.offset.y = 0.1,
  just = "center",
  along_lines = TRUE,
  bg.padding = 0.4,
  clustering = TRUE,
  point.label = TRUE,
  point.label.gap = 0.4,
  point.label.method = "SANN",
  remove_overlap = FALSE,
  dots.just = NA,
  dots.icon.scale = 3,
  dots.grob.dim = c(width = 48, height = 48, render.width = 256, render.height = 256)
)

opt_tm_symbols(
  points_only = "ifany",
  point_per = "feature",
  on_surface = FALSE,
  icon.scale = 3,
  just = NA,
  grob.dim = c(width = 48, height = 48, render.width = 256, render.height = 256)
)

opt_tm_dots(
  points_only = "ifany",
  point_per = "feature",
  on_surface = FALSE,
  icon.scale = 3,
  just = NA,
  grob.dim = c(width = 48, height = 48, render.width = 256, render.height = 256)
)

opt_tm_bubbles(
  points_only = "ifany",
  point_per = "feature",
  on_surface = FALSE,
  icon.scale = 3,
  just = NA,
  grob.dim = c(width = 48, height = 48, render.width = 256, render.height = 256)
)

opt_tm_squares(
  points_only = "ifany",
  point_per = "feature",
  on_surface = FALSE,
  icon.scale = 3,
  just = NA,
  grob.dim = c(width = 48, height = 48, render.width = 256, render.height = 256)
)

Arguments

size, size.scale, size.legend, size.chart, size.free: Visual variable that determines the size. See details.
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.
shape, shape.scale, shape.legend, shape.chart, shape.free: Visual variable that determines the shape. 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.legend, fill_alpha.chart, fill_alpha.free: Visual variable that determines the fill color transparency. See details. the fill color alpha 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.
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
text, text.scale, text.legend, text.chart, text.free: Visual variable that determines the text. See details.
fontface, fontface.scale, fontface.legend, fontface.chart, fontface.free: Visual variable that determines the font face. See details.
fontfamily: The font family. See gpar() for details.
bgcol, bgcol.scale, bgcol.legend, bgcol.chart, bgcol.free: Visual variable that determines the background color. See Details.
bgcol_alpha, bgcol_alpha.scale, bgcol_alpha.legend, bgcol_alpha.chart, bgcol_alpha.free: Visual variable that determines the background color transparency. See Details.
xmod, xmod.scale, xmod.legend, xmod.chart, xmod.free: Transformation variable that determines the x offset. See details.
ymod, ymod.scale, ymod.legend, ymod.chart, ymod.free: Transformation variable that determines the y offset. See details. the text. See details.
angle, angle.scale, angle.legend, angle.chart, angle.free: Rotation angle
markers_on_top_of_text: should markers be plot on top of the text (by default FALSE)
points_only: should only point geometries of the shape object (defined in tm_shape()) be plotted? By default "ifany", which means TRUE in case a geometry collection is specified.
point_per: specification of how spatial points are mapped when the geometry is a multi line or a multi polygon. One of "feature", "segment" or "largest". The first generates a spatial point for every feature, the second for every segment (i.e. subfeature), the third only for the largest segment (subfeature). Note that the last two options can be significant slower.
on_surface: In case of polygons, centroids are computed. Should the points be on the surface? If TRUE, which is slower than the default FALSE, centroids outside the surface are replaced with points computed with sf::st_point_on_surface().
shadow: Shadow behind the text. Logical or color.
shadow.offset.x, shadow.offset.y: Shadow offset in line heights
just: justification of the text relative to the point coordinates. Either one of the following values: "left" , "right", "center", "bottom", and "top", or a vector of two values where first value specifies horizontal and the second value vertical justification. Besides the mentioned values, also numeric values between 0 and 1 can be used. 0 means left justification for the first value and bottom justification for the second value. Note that in view mode, only one value is used.
along_lines: logical that determines whether labels are rotated along the spatial lines. Only applicable if a spatial lines shape is used.
bg.padding: The padding of the background in terms of line heights.
clustering: value that determines whether the text labels are clustered in "view" mode. One of: TRUE, FALSE, or the output of markerClusterOptions.
point.label: logical that determines whether the labels are placed automatically. By default FALSE for tm_text, and TRUE for tm_labels if the number of labels is less than 500 (otherwise it will be too slow).
point.label.gap: numeric that determines the gap between the point and label
point.label.method: the optimization method, either "SANN" for simulated annealing (the default) or "GA" for a genetic algorithm.
remove_overlap: logical that determines whether the overlapping labels are removed
dots.just: justification of the text relative to the point coordinates. Either one of the following values: "left" , "right", "center", "bottom", and "top", or a vector of two values where first value specifies horizontal and the second value vertical justification. Besides the mentioned values, also numeric values between 0 and 1 can be used. 0 means left justification for the first value and bottom justification for the second value. Note that in view mode, only one value is used.
dots.icon.scale: scaling number that determines how large the icons (or grobs) are in plot mode in comparison to proportional symbols (such as bubbles). In view mode, the size is determined by the icon specification (see tmap_icons) or, if grobs are specified by grob.width and grob.height
dots.grob.dim: vector of four values that determine how grob objects (see details) are shown in view mode. The first and second value are the width and height of the displayed icon. The third and fourth value are the width and height of the rendered png image that is used for the icon. Generally, the third and fourth value should be large enough to render a ggplot2 graphic successfully. Only needed for the view mode.
icon.scale: scaling number that determines how large the icons (or grobs) are in plot mode in comparison to proportional symbols (such as bubbles). For view mode, use the argument grob.dim
grob.dim: vector of four values that determine how grob objects (see details) are shown in view mode. The first and second value are the width and height of the displayed icon. The third and fourth value are the width and height of the rendered png image that is used for the icon. Generally, the third and fourth value should be large enough to render a ggplot2 graphic successfully. Only needed for the view mode.

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.

A symbol shape specification is one of the following three options.

A numeric value that specifies the plotting character of the symbol. See parameter pch of points and the last example to create a plot with all options. Note that this is not supported for the "view" mode.
A grob object, which can be a ggplot2 plot object created with ggplotGrob. To specify multiple shapes, a list of grob objects is required. See example of a proportional symbol map with ggplot2 plots.
An icon specification, which can be created with tmap_icons.

To specify multiple shapes (needed for the shapes argument), a vector or list of these shape specification is required. The shape specification options can also be mixed. For the shapes argument, it is possible to use a named vector or list, where the names correspond to the value of the variable specified by the shape argument. For small multiples, a list of these shape specification(s) should be provided.

Examples

metroAfrica = sf::st_intersection(metro, World[World$continent == "Africa", ])
#> Warning: attribute variables are assumed to be spatially constant throughout all geometries
Africa = World[World$continent == "Africa", ]

# to do: update land
library(sf)
st_crs(land) = 4326

tm_shape(land) +
  tm_raster("cover_cls",
        col.scale = tm_scale(
          values = cols4all::c4a("brewer.pastel1")[c(3,7,7,2,6,1,2,2)]
        ),
        col.legend = tm_legend_hide()) +
  tm_shape(rivers) +
  tm_lines(lwd = "strokelwd", lwd.scale = tm_scale_asis(values.scale = .3),
       col = cols4all::c4a("brewer.pastel1")[2]) +
  tm_shape(Africa, is.main = TRUE) +
  tm_borders() +
  tm_shape(metroAfrica) +
  tm_symbols(fill = "red", shape = "pop2020", size = "pop2020",
         size.scale = tm_scale_intervals(
              breaks = c(1, 2, 5, 10, 15, 20, 25) * 1e6,
              values.range = c(0.2,2)
           ),
         size.legend = tm_legend("Population in 2020"),
         shape.scale = tm_scale_intervals(
              breaks = c(1, 2, 5, 10, 15, 20, 25) * 1e6,
              values = c(21, 23, 22, 21, 23, 22)
           ),
         shape.legend = tm_legend_combine("size")) +
  tm_labels("name", options = opt_tm_labels(remove_overlap = FALSE))


## to do: replace this example:

if (FALSE) { # \dontrun{
  if (require(rnaturalearth)) {

    airports <- ne_download(scale=10, type="airports", returnclass = "sf")
    airplane <- tmap_icons(system.file("img/airplane.png", package = "tmap"))



    current.mode <- tmap_mode("view")

    tm_shape(NLD_prov, crs = 4326) +
      tm_polygons() +
    tm_shape(airports) +
      tm_symbols(shape = airplane,
             size = "natlscale",
             size.legend = tm_legend_hide(),
             id = "name"
             ) +
      tm_text(text = "name")

    tmap_mode(current.mode)
  }
} # }

########################
## plot symbol shapes
########################

# create grid of 25 points in the Atlantic
atlantic_grid = cbind(expand.grid(x = -51:-47, y = 20:24), id = seq_len(25))
x = sf::st_as_sf(atlantic_grid, coords = c("x", "y"), crs = 4326)

tm_shape(x, bbox = tmaptools::bb(x, ext = 1.2)) +
  tm_symbols(shape = "id",
         size = 2,
         lwd = 2,
         fill = "orange",
         col = "black",
         shape.scale = tm_scale_asis()) +
  tm_text("id", ymod = -2)


# also supported in view mode :-)