tmap (version 1.0)

tm_raster: Draw a raster

Description

Creates a tmap-element that draws a raster. Either a fixed color is used, or a color palette is mapped to a data variable. By default, a divering color palette is used for numeric variables and a qualitative palette for categorical variables.

Usage

tm_raster(col = "grey70", alpha = NA, palette = NULL, n = 5,
  style = "pretty", breaks = NULL, labels = NULL,
  auto.palette.mapping = TRUE, contrast = 1, max.categories = 12,
  colorNA = NA, textNA = "Missing", text_separator = "to",
  text_less_than = "Less than", text_or_more = "or more", title = NA,
  legend.is.portrait = TRUE, legend.hist = FALSE, legend.hist.title = NA,
  legend.z = NA, legend.hist.z = NA)

Arguments

col

either a single color value or the name of a data variable that is contained in shp. In the latter case, either the data variable contains color values, or values (numeric or categorical) that will be depicted by a color palette (see pa

alpha

transparency number between 0 (totally transparent) and 1 (not transparent). By default, the alpha value of the col is used (normally 1).

palette

palette name. See RColorBrewer::display.brewer.all() for options. Use a "-" as prefix to reverse the palette. By default, "RdYlGn" is taken for numeric variables and "Dark2" for categorical variables.

n

preferred number of classes (in case col is a numeric variable)

style

method to cut the color scale (in case col is a numeric variable): e.g. "fixed", "equal", "pretty", "quantile", or "kmeans". See the details in classIntervals.

breaks

in case style=="fixed", breaks should be specified

labels

labels of the classes

auto.palette.mapping

When diverging colour palettes are used (i.e. "RdBu") this method automatically maps colors to values such that the middle colors (mostly white or yellow) are assigned to values of 0, and the two sides of the color palette are assigned to negative respect

contrast

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 t

max.categories

in case col is the name of a categorical variable, this value determines how many categories (levels) it can have maximally. If the number of levels is higher than max.categories, then levels are combined.

colorNA

color used for missing values

textNA

text used for missing values. Use NA to omit text for missing values in the legend

text_separator

Character string to use to separate numbers in the legend (default: "to").

text_less_than

Character string to use to translate "Less than" (which is the default).

text_or_more

Character string to use to translate "or more" (which is the default).

title

title of the legend element

legend.is.portrait

logical that determines whether the legend is in portrait mode (TRUE) or landscape (FALSE)

legend.hist

logical that determines whether a histogram is shown

legend.hist.title

title for the histogram. By default, one title is used for both the histogram and the normal legend.

legend.z

index value that determines the position of the legend element 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.

legend.hist.z

index value that determines the position of the histogram legend element

Value

• tmap-element

See Also

../doc/tmap-nutshell.html{vignette("tmap-nutshell")}

Examples

data(land)
data(World)

pal20 <- c("#003200", "#3C9600", "#006E00", "#556E19", "#00C800", "#8CBE8C",
		     "#467864", "#B4E664", "#9BC832", "#EBFF64", "#F06432", "#9132E6",
		     "#E664E6", "#9B82E6", "#B4FEF0", "#646464", "#C8C8C8", "#FF0000",
		     "#FFFFFF", "#5ADCDC")
tm_shape(land) +
    tm_raster("cover", max.categories = 20, palette=pal20, title="Global Land Cover") + 
tm_layout_World(inner.margins=0, legend.position = c("left","bottom"))

pal8 <- c("#33A02C", "#B2DF8A", "#FDBF6F", "#1F78B4", "#999999", "#E31A1C", "#E6E6E6", "#A6CEE3")
tm_shape(land, ylim = c(-88,88), relative=FALSE) +
    tm_raster("cover_cls", palette = pal8, title="Global Land Cover") +
tm_shape(World) +
    tm_borders() +
tm_layout_World(inner.margins=0,
    legend.position = c("left","bottom"),
    legend.bg.color = "white", legend.bg.alpha=.2, 
    legend.frame="gray50", legend.width=.2)

tm_shape(land, ylim = c(-88,88), relative=FALSE) +
    tm_raster("trees", palette = "Greens", title="Percent Tree Cover") +
tm_shape(World) +
    tm_borders() +
tm_layout(inner.margins=0, 
    legend.position = c("left","bottom"), bg.color="lightblue")

tm_shape(land) +
    tm_raster("black") +
    tm_facets(by="cover_cls") +
tm_layout(inner.margins=0, 
    title.position = c("left", "bottom"), title.bg.color="gray80")