Creates a tmap-element
that adds a manual legend.
Usage
tm_add_legend(
type = c("fill", "symbol", "text", "line", "title"),
labels = NULL,
col = NULL,
size = NULL,
shape = NULL,
lwd = NULL,
lty = NULL,
text = NULL,
alpha = NA,
border.col = "black",
border.lwd = 1,
border.alpha = NA,
title = "",
is.portrait = TRUE,
legend.format = list(),
reverse = FALSE,
z = NA,
zindex = NA,
group = NULL
)
Arguments
- type
type of legend. One of
"fill"
,"symbol"
,"text"
,"line"
, or"title"
. The last option only displays a title.- labels
legend labels
- col
legend colors
- size
legend symbol sizes (if
type=="symbol"
). See example how to replicate the sizes of symbols created withtm_symbols
. If not specified, the symbols will have the same size as when callingtm_symbols
without specifying thesize
argument.- shape
legend symbol shapes (if
type=="symbol"
)- lwd
legend line widths (if
type=="line"
)- lty
legend line types (if
type=="line"
)- text
legend texts (if
type=="text"
)- alpha
legend fill transparency
- border.col
legend border col (if
type
is"fill"
or"symbol"
)- border.lwd
legend border width (if
type
is"fill"
or"symbol"
)- border.alpha
legend border alpha (if
type
is"fill"
or"symbol"
)- title
legend title
- is.portrait
is legend portrait (
TRUE
) or landscape (FALSE
)?- legend.format
options to format the legend, see
tm_symbols
(the description of the argumentlegend.format
) for details. Note that many of these arguments are not applicable fortm_add_legend
sincelabels
should be a character vector. However, some options could still be handy, e.g.list(text.align = "right")
.- reverse
are the legend items reversed (by default
FALSE
)?- z
legend stack position
- zindex
zindex of the pane in view mode to which the legend belongs (if any).
- group
name of the group to which this layer belongs in view mode. Each group can be selected or deselected in the layer control item. By default
NULL
, which means that the legend will not be shown in the layer control item.
See also
tm_symbols
for another example
Examples
# This example adds a manual legend that combines the tm_symbols color and size legend.
if (FALSE) { # \dontrun{
data(World)
data(metro)
# legend bubble size (10, 20, 30, 40 million) are
# - are normlized by upper limit (40e6),
# - square rooted (see argument perceptual of tm_symbols), and
# - scaled by 2:
bubble_sizes <- ((c(10, 20, 30, 40) * 1e6) / 40e6) ^ 0.5 * 2
tm_shape(World) +
tm_polygons() +
tm_shape(metro) +
tm_symbols(col='pop2020',
breaks = c(0, 15, 25, 35, 40) * 1e6,
n=4,
palette = 'YlOrRd',
size='pop2020',
sizes.legend = c(10, 20, 30, 40) * 1e6,
size.lim = c(0, 40e6),
scale = 2,
legend.size.show = FALSE, # comment this line to see the original size legend
legend.col.show = FALSE, # comment this line to see the original color legend
legend.size.is.portrait = TRUE) +
tm_add_legend('symbol',
col = RColorBrewer::brewer.pal(4, "YlOrRd"),
border.col = "grey40",
size = bubble_sizes,
labels = c('0-15 mln','15-25 mln','25-35 mln','35-40 mln'),
title="Population Estimate")
} # }
# See also the documentation of tm_symbols for another example