Creates a tmap-element that draws symbols, including symbols and dots. The color, size, and shape of the symbols can be mapped to data variables.
tm_symbols(size = 1, col = NA, shape = 21, alpha = NA,
border.col = NA, border.lwd = 1, border.alpha = NA, scale = 1,
perceptual = FALSE, clustering = FALSE, size.max = NA, size.lim = NA,
sizes.legend = NULL, sizes.legend.labels = NULL, n = 5,
style = ifelse(is.null(breaks), "pretty", "fixed"), breaks = NULL,
interval.closure = "left", palette = NULL, labels = NULL,
midpoint = NULL, stretch.palette = TRUE, contrast = NA, colorNA = NA,
textNA = "Missing", showNA = NA, colorNULL = NA, shapes = 21:25,
shapes.legend = NULL, shapes.legend.fill = NA, shapes.labels = NULL,
shapeNA = 4, shape.textNA = "Missing", shape.showNA = NA,
shapes.n = 5, shapes.style = ifelse(is.null(shapes.breaks), "pretty",
"fixed"), shapes.breaks = NULL, shapes.interval.closure = "left",
legend.max.symbol.size = 0.8, just = NA, jitter = 0, xmod = 0,
ymod = 0, icon.scale = 3, grob.dim = c(width = 48, height = 48,
render.width = 256, render.height = 256), title.size = NA, title.col = NA,
title.shape = NA, legend.size.show = TRUE, legend.col.show = TRUE,
legend.shape.show = TRUE, legend.format = list(),
legend.size.is.portrait = FALSE, legend.col.is.portrait = TRUE,
legend.shape.is.portrait = TRUE, legend.size.reverse = FALSE,
legend.col.reverse = FALSE, legend.shape.reverse = FALSE,
legend.hist = FALSE, legend.hist.title = NA, legend.size.z = NA,
legend.col.z = NA, legend.shape.z = NA, legend.hist.z = NA, id = NA,
popup.vars = NA, popup.format = list(), group = NA,
auto.palette.mapping = NULL, max.categories = NULL)tm_squares(size = 1, col = NA, shape = 22, scale = 4/3, ...)
tm_bubbles(size = 1, col = NA, shape = 21, scale = 4/3,
legend.max.symbol.size = 1, ...)
tm_dots(col = NA, size = 0.02, shape = 16, title = NA,
legend.show = TRUE, legend.is.portrait = TRUE, legend.z = NA, ...)
tm_markers(shape = marker_icon(), col = NA, border.col = NULL,
clustering = TRUE, text = NULL, text.just = "top",
markers.on.top.of.text = TRUE, group = NA, ...)
a single value or a shp data variable that determines the symbol sizes. The reference value size=1 corresponds to the area of symbols that have the same height as one line of text. If a data variable is provided, the symbol sizes are scaled proportionally (or perceptually, see perceptual) where by default the symbol with the largest data value will get size=1 (see also size.max). If multiple values are specified, small multiples are drawn (see details).
color(s) of the symbol. Either a color (vector), or categorical variable name(s). If multiple values are specified, small multiples are drawn (see details).
shape(s) of the symbol. Either direct shape specification(s) or a data variable name(s) that is mapped to the symbols specified by the shapes argument. See details for the shape specification.
transparency number between 0 (totally transparent) and 1 (not transparent). By default, the alpha value of the col is used (normally 1).
color of the symbol borders.
line width of the symbol borders. If NA, no symbol borders are drawn.
transparency number, regarding the symbol borders, between 0 (totally transparent) and 1 (not transparent). By default, the alpha value of the col is used (normally 1).
symbol size multiplier number.
logical that determines whether symbols are scales with a perceptually (TRUE) or mathematically (FALSE, default value). The perceived area of larger symbols is often underestimated. Flannery (1971) experimentally derived a method to compensate this for symbols, which is enabled by this argument.
value that determines whether the symbols are clustered in "view" mode. It does not work proportional bubbles (i.e. tm_bubbles). One of: TRUE, FALSE, or the output of markerClusterOptions.
value that is mapped to size=1. By default (NA), the maximum data value is chosen. Only applicable when size is the name of a numeric variable of shp
vector of two limit values of the size variable. Only symbols are drawn whose value is greater than or equal to the first value. Symbols whose values exceed the second value are drawn at the size of the second value. Only applicable when size is the name of a numeric variable of shp
vector of symbol sizes that are shown in the legend. By default, this is determined automatically.
vector of labels for that correspond to sizes.legend.
preferred number of color scale classes. Only applicable when col is a numeric variable name.
method to process the color scale when col is a numeric variable. Discrete options are "cat", "fixed", "sd", "equal", "pretty", "quantile", "kmeans", "hclust", "bclust", "fisher", and "jenks". A numeric variable is processed as a categorical variable when using "cat", i.e. each unique value will correspond to a distinct category. For the other discrete options, see the details in classIntervals. Continuous options are "cont" and "order". The former maps the values of col to a smooth gradient, whereas the latter maps the order of values of col to a smooth gradient. They are the continuous variants of respectively the discrete methods "equal" and quantile".
in case style=="fixed", breaks should be specified. The breaks argument can also be used when style="cont". In that case, the breaks are mapped evenly to the sequential or diverging color palette.
value that determines whether where the intervals are closed: "left" or "right". Only applicable if col is a numeric variable.
a palette name or a vector of colors. See tmaptools::palette_explorer() for the named palettes. Use a "-" as prefix to reverse the palette. The default palette is taken from tm_layout's argument aes.palette, which typically depends on the style. The type of palette from aes.palette is automatically determined, but can be overwritten: use "seq" for sequential, "div" for diverging, and "cat" for categorical.
labels of the classes
The value mapped to the middle color of a diverging palette. By default it is set to 0 if negative and positive values are present. In that case, the two sides of the color palette are assigned to negative respectively positive values. If all values are positive or all values are negative, then the midpoint is set to NA, which means that the value that corresponds to the middle color class (see style) is mapped to the middle color. Only applies when col is a numeric variable. If it is specified for sequential color palettes (e.g. "Blues"), then this color palette will be treated as a diverging color palette.
Logical that determines whether the categorical color palette should be stretched if there are more categories than colors. If TRUE (default), interpolated colors are used (like a rainbow). If FALSE, the palette is repeated.
vector of two numbers that determine the range that is used for sequential and diverging palettes (applicable when auto.palette.mapping=TRUE). Both numbers should be between 0 and 1. The first number determines where the palette begins, and the second number where it ends. For sequential palettes, 0 means the brightest color, and 1 the darkest color. For diverging palettes, 0 means the middle color, and 1 both extremes. If only one number is provided, this number is interpreted as the endpoint (with 0 taken as the start).
colour for missing values. Use NULL for transparency.
text used for missing values of the color variable.
logical that determines whether missing values are named in the legend. By default (NA), this depends on the presence of missing values.
colour for polygons that are shown on the map that are out of scope
palette of symbol shapes. Only applicable if shape is a (vector of) categorical variable(s). See details for the shape specification. By default, the filled symbols 21 to 25 are taken.
symbol shapes that are used in the legend (instead of the symbols specified with shape. Especially useful when shapes consist of grobs that have to be represented by neutrally colored shapes (see also shapes.legend.fill.
Fill color of legend shapes (see shapes.legend)
Legend labels for the symbol shapes
the shape (a number or grob) for missing values. By default a cross (number 4). Set to NA to hide symbols for missing values.
text used for missing values of the shape variable.
logical that determines whether missing values are named in the legend. By default (NA), this depends on the presence of missing values.
preferred number of shape classes. Only applicable when shape is a numeric variable name.
method to process the shape scale when shape is a numeric variable. See style argument for options
in case shapes.style=="fixed", breaks should be specified
value that determines whether where the intervals are closed: "left" or "right". Only applicable if shape is a numeric variable.
Maximum size of the symbols that are drawn in the legend. For circles and bubbles, a value larger than one is recommended (and used for tm_bubbles)
justification of the symbols 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 alignment and 1 right alignment. The default value is c("center", "center"). For icons, this value may already be speficied (see tmap_icons). The just, if specified, will overrides this.
number that determines the amount of jittering, i.e. the random noise added to the position of the symbols. 0 means no jittering is applied, any positive number means that the random noise has a standard deviation of jitter times the height of one line of text line.
horizontal position modification of the symbols, in terms of the height of one line of text. Either a single number for all polygons, or a numeric variable in the shape data specifying a number for each polygon. Together with ymod, it determines position modification of the symbols. See also jitter for random position modifications. In most coordinate systems (projections), the origin is located at the bottom left, so negative xmod move the symbols to the left, and negative ymod values to the bottom.
vertical position modification. See xmod.
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.heigth
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.
title of the legend element regarding the symbol sizes
title of the legend element regarding the symbol colors
title of the legend element regarding the symbol shapes
logical that determines whether the legend for the symbol sizes is shown
logical that determines whether the legend for the symbol colors is shown
logical that determines whether the legend for the symbol shapes is shown
list of formatting options for the legend numbers. Only applicable if labels is undefined. Parameters are:
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.
Should the labels be formatted scientifically? 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.
By default, "f", i.e. the standard notation xxx.xxx, is used. If scientific=TRUE then "g", which means that numbers are formatted scientifically, i.e. n.dddE+nn if needed to save space.
Number of digits after the decimal point if format="f", and the number of significant digits otherwise.
Character string to use to separate numbers in the legend (default: "to").
Character value(s) to use to translate "Less than". When a character vector of length 2 is specified, one for each word, these words are aligned when text.to.columns = TRUE
Character value(s) to use to translate "or more". When a character vector of length 2 is specified, one for each word, these words are aligned when text.to.columns = TRUE
Value that determines how the numbers are aligned, "left", "center" or "right"
Logical that determines whether the text is aligned to three columns (from, text.separator, to). By default FALSE.
Other arguments passed on to formatC
logical that determines whether the legend element regarding the symbol sizes is in portrait mode (TRUE) or landscape (FALSE)
logical that determines whether the legend element regarding the symbol colors is in portrait mode (TRUE) or landscape (FALSE)
logical that determines whether the legend element regarding the symbol shapes is in portrait mode (TRUE) or landscape (FALSE)
logical that determines whether the items of the legend regarding the symbol sizes are shown in reverse order, i.e. from bottom to top when legend.size.is.portrait = TRUE and from right to left when legend.size.is.portrait = FALSE
logical that determines whether the items of the legend regarding the symbol colors are shown in reverse order, i.e. from bottom to top when legend.col.is.portrait = TRUE and from right to left when legend.col.is.portrait = FALSE
logical that determines whether the items of the legend regarding the symbol shapes are shown in reverse order, i.e. from bottom to top when legend.shape.is.portrait = TRUE and from right to left when legend.shape.is.portrait = FALSE
logical that determines whether a histogram is shown regarding the symbol colors
title for the histogram. By default, one title is used for both the histogram and the normal legend for symbol colors.
index value that determines the position of the legend element regarding the symbol sizes with respect to other legend elements. The legend elements are stacked according to their z values. The legend element with the lowest z value is placed on top.
index value that determines the position of the legend element regarding the symbol colors. (See legend.size.z)
index value that determines the position of the legend element regarding the symbol shapes. (See legend.size.z)
index value that determines the position of the histogram legend element. (See legend.size.z)
name of the data variable that specifies the indices of the symbols. Only used for "view" mode (see tmap_mode).
names of data variables that are shown in the popups in "view" mode. If NA (default), only aesthetic variables (i.e. specified by col and lwd) are shown). If they are not specified, all variables are shown. Set popup.vars to FALSE to disable popups. When a vector of variable names is provided, the names (if specified) are printed in the popups.
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.
name of the group to which this layer belongs in view mode. Each group can be selected or deselected in the layer control item. Groups can either be specified as base or overlay groups in tm_view (arguments base.groups and overlay.groups).
deprecated. It has been replaced by midpoint for numeric variables and stretch.palette for categorical variables.
deprecated. It has moved to tmap_options.
arguments passed on to tm_symbols. For tm_markers, arguments can also be passed on to tm_text. In that case, they have to be prefixed with text., e.g. the col argument should be names text.col
shortcut for title.col for tm_dots
shortcut for legend.col.show for tm_dots
shortcut for legend.col.is.portrait for tm_dots
shortcut for legend.col.z shortcut for tm_dots
text of the markers. Shown in plot mode, and as popup text in view mode.
justification of marker text (see just argument of tm_text). Only applicable in plot mode.
For tm_markers, should the markers be drawn on top of the text labels?
Small multiples can be drawn in two ways: either by specifying the by argument in tm_facets, or by defining multiple variables in the aesthetic arguments, which are size, col, and shape. In the latter case, the arguments, except for the ones starting with legend., can be specified for small multiples as follows. If the argument normally only takes a single value, such as n, then a vector of those values can be specified, one for each small multiple. If the argument normally can take a vector, such as palette, then a list of those vectors (or values) can be specified, one for each small multiple.
A shape specification is one of the following three options. 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.
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.
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.
For small multiples, a list of these shape specification(s) should be provided.
Flannery J (1971). The Relative Effectiveness of Some Common Graduated Point Symbols in the Presentation of Quantitative Data. Canadian Cartographer, 8(2), 96-109.
Tennekes, M., 2018, tmap: Thematic Maps in R, Journal of Statistical Software, 84(6), 1-39, DOI
# NOT RUN {
data(World, metro)
metro$growth <- (metro$pop2020 - metro$pop2010) / (metro$pop2010 * 10) * 100
tm_shape(World) +
tm_fill("grey70") +
tm_shape(metro) +
tm_bubbles("pop2010", col = "growth",
border.col = "black", border.alpha = .5,
style="fixed", breaks=c(-Inf, seq(0, 6, by=2), Inf),
palette="-RdYlBu", contrast=1,
title.size="Metro population",
title.col="Growth rate (%)") +
tm_format("World")
tm_shape(metro) +
tm_symbols(size = "pop2010", col="pop2010", shape="pop2010",
legend.format = list(text.align="right", text.to.columns = TRUE)) +
tm_legend(outside = TRUE, outside.position = "bottom", stack = "horizontal")
if (require(ggplot2) && require(dplyr) && require(tidyr) && require(tmaptools) && require(sf)) {
data(NLD_prov)
origin_data <- NLD_prov %>%
st_set_geometry(NULL) %>%
mutate(FID= factor(1:n())) %>%
select(FID, origin_native, origin_west, origin_non_west) %>%
gather(key=origin, value=perc, origin_native, origin_west, origin_non_west, factor_key=TRUE)
origin_cols <- get_brewer_pal("Dark2", 3)
grobs <- lapply(split(origin_data, origin_data$FID), function(x) {
ggplotGrob(ggplot(x, aes(x="", y=-perc, fill=origin)) +
geom_bar(width=1, stat="identity") +
scale_y_continuous(expand=c(0,0)) +
scale_fill_manual(values=origin_cols) +
theme_ps(plot.axes = FALSE))
})
names(grobs) <- NLD_prov$name
tm_shape(NLD_prov) +
tm_polygons() +
tm_symbols(size="population", shape="name",
shapes=grobs,
sizes.legend=c(.5, 1,3)*1e6,
scale=1,
legend.shape.show = FALSE,
legend.size.is.portrait = TRUE,
shapes.legend = 22,
title.size = "Population",
id = "name",
popup.vars = c("population", "origin_native",
"origin_west", "origin_non_west")) +
tm_add_legend(type="fill",
col=origin_cols,
labels=c("Native", "Western", "Non-western"),
title="Origin") +
tm_format("NLD")
}
# TIP: check out these examples in view mode, enabled with tmap_mode("view")
# }
# NOT RUN {
if (require(rnaturalearth)) {
airports <- ne_download(scale=10, type="airports")
airplane <- tmap_icons(system.file("img/airplane.png", package = "tmap"))
current.mode <- tmap_mode("view")
tm_shape(airports) +
tm_symbols(shape=airplane, size="natlscale",
legend.size.show = FALSE, scale=1, border.col = NULL, id="name", popup.vars = TRUE) +
tm_view(set.view = c(lon = 15, lat = 48, zoom = 4))
tmap_mode(current.mode)
}
# }
# NOT RUN {
#####################################################################################
# }
# NOT RUN {
# plot all available symbol shapes:
if (require(ggplot2)) {
ggplot(data.frame(p=c(0:25,32:127))) +
geom_point(aes(x=p%%16, y=-(p%/%16), shape=p), size=5, fill="red") +
geom_text(mapping=aes(x=p%%16, y=-(p%/%16+0.25), label=p), size=3) +
scale_shape_identity() +
theme(axis.title=element_blank(),
axis.text=element_blank(),
axis.ticks=element_blank(),
panel.background=element_blank())
}
# }
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