plot: Make a map
In terra: Spatial Data Analysis

plot	R Documentation

Make a map

Description

Plot the values of a SpatRaster or SpatVector to make a map.

See points, lines or polys to add a SpatVector to an existing map (or use argument add=TRUE).

There is a separate help file for plotting a SpatGraticule or SpatExtent.

Usage

## S4 method for signature 'SpatRaster,numeric'
plot(x, y=1, col, type=NULL, mar=NULL, legend=TRUE, axes=!add, plg=list(), pax=list(), 
    maxcell=500000, smooth=FALSE, range=NULL, fill_range=FALSE, levels=NULL, 
	all_levels=FALSE, breaks=NULL, breakby="eqint", fun=NULL, colNA=NULL, 
	alpha=NULL, sort=FALSE,  reverse=FALSE, grid=FALSE, ext=NULL, reset=FALSE, 
	add=FALSE, buffer=FALSE, background=NULL, box=axes, clip=TRUE, overview=NULL, ...)

## S4 method for signature 'SpatRaster,missing'
plot(x, y, main, mar=NULL, nc, nr, maxnl=16, maxcell=500000, add=FALSE, 
	plg=list(), pax=list(), ...)

## S4 method for signature 'SpatRaster,character'
plot(x, y, ...)

## S4 method for signature 'SpatVector,character'
plot(x, y, col=NULL, type=NULL, mar=NULL, add=FALSE, legend=TRUE, axes=!add, 
    main="", buffer=TRUE, background=NULL, grid=FALSE, ext=NULL, sort=TRUE, 
	reverse=FALSE, fun=NULL, plg=list(), pax=list(), nr, nc, colNA=NA, alpha=NULL, 
	box=axes, clip=TRUE, ...)

## S4 method for signature 'SpatVector,numeric'
plot(x, y, ...)

## S4 method for signature 'SpatVector,missing'
plot(x, y, values=NULL, ...)

## S4 method for signature 'SpatVectorCollection,missing'
plot(x, y, main, mar=NULL, nc, nr, maxnl=16, ...)

## S4 method for signature 'SpatVectorCollection,numeric'
plot(x, y, main, mar=NULL, ext=NULL, ...)

Arguments

`x`	SpatRaster or SpatVector
`y`	missing or positive integer or name indicating the layer(s) to be plotted
`col`	character vector to specify the colors to use. The default is `map.pal("viridis", 100)`. The default can be changed with the `terra.pal` option. For example: `options(terra.pal=terrain.colors(10))`. If `x` is a `SpatRaster`, it can also be a `data.frame` with two columns (value, color) to get a "classes" type legend or with three columns (from, to, color) to get an "interval" type legend
`type`	character. Type of map/legend. One of "continuous", "classes", or "interval". If not specified, the type is chosen based on the data
`mar`	numeric vector of length 4 to set the margins of the plot (to make space for the legend). The default is (3.1, 3.1, 2.1, 7.1) for a single plot with a legend and (3.1, 3.1, 2.1, 2.1) otherwise. The default for a RGB raster is 0. Use `mar=NA` to not set the margins
`legend`	logical or character. If not `FALSE` a legend is drawn. The character value can be used to indicate where the legend is to be drawn. For example "topright" or "bottomleft". Use `plg` for more refined placement. Not supported for continuous legends (the default for raster data)
`axes`	logical. Draw axes?
`buffer`	logical. If `TRUE` the plotting area is made slightly larger than the extent of `x`
`background`	background color. Default is no color (white)
`box`	logical. Should a box be drawn around the map?
`clip`	logical. Should the axes be clipped to the extent of `x`?
`overview`	logical. Should "overviews" be used for fast rendering? This can result in much faster plotting of raster files that have overviews (e.g. "COG" format) and are accessed over a http connection. However, these overviews generally show aggregate values, thus reducing the range of the actual values. If `NULL`, the argument is set to `TRUE` for rasters that are accessed over http and `FALSE` in other cases
`plg`	list with parameters for drawing the legend. See the arguments for `legend`. In addition there are these parameters for the legend title: `title.srt` to rotate the title and `title.x` and `title.y` to place the title at specific coordinates. Parameter `digits` can be used to change the number of digits to print after the decimal point. A legend can be placed with placed by specifying arguments `x` and `y`. For a continuous legend `y` can have two values. `x` can also be a SpatExtent. Furthermore, `x` can have be a keyword such "topleft" and "bottomright" to place the legend at these locations inside the map rectangle. For a continuous legend, only the placement keywords "left", "right", "top", "bottom", "topright", "bottomright" are recognized; and when using these keywords, the legend is placed outside of the map rectangle. The placement of the legend can be altered with argument `nudge` that move the location in the directions specified with one value (x direction) or two values (x, y). For a continuous legend it can also have four values (xmin, xmax, ymin, ymax). Additional parameters for continuous legends include: `size` to change the height and/or width; the defaults are `c(1,1)` `at` to set the location of the tic-marks `tic` One of these partially matched values: "through", "in", "middle", "out", or "none", to choose a tic-mark placement/length that is different from the default "throughout". You can also set `tic.col`, `tic.box.col` and `tic.lwd`
`pax`	list with parameters for drawing axes. See the arguments for `axis`. Arguments `side`, `tick` and `lab` can be used to indicate for which of the four axes to draw a line (side), tick-mark, and/or the tick-mark labels. The default is `c(1:4)` for side and `1:2` for the other two. If `side` is changed the other two default to that value. Logical argument `retro` can be used to use a sexagesimal notation for the labels (degrees/minutes/hemisphere) instead of the standard decimal notation
`maxcell`	positive integer. Maximum number of cells to use for the plot
`smooth`	logical. If `TRUE` the cell values are smoothed (only if a continuous legend is used)
`range`	numeric. minimum and maximum values to be used for the continuous legend. You can use `NA` for one of these to only set the minimum or maximum value
`fill_range`	logical. If `TRUE`, values outside of `range` get the colors of the extreme values; otherwise they get colored as `NA`
`levels`	character. labels for the legend when `type="classes"`
`all_levels`	logical. If `TRUE`, the legend shows all levels of a categorical raster, even if they are not present in the data
`breaks`	numeric. Either a single number to indicate the number of breaks desired, or the actual breaks. When providing this argument, the default legend becomes "interval"
`breakby`	character or function. Either "eqint" for equal interval breaks, "cases" for equal quantile breaks. If a function is supplied, it should take a single argument (a vector of values) and create groups
`fun`	function to be called after plotting each SpatRaster layer to add something to each map (such as text, legend, lines). For example, with SpatVector `v`, you could do `fun=function() lines(v)`. The function may have one argument, representing the layer that is plotted (1 to the number of layers)
`colNA`	character. color for the NA values
`alpha`	Either a single numeric between 0 and 1 to set the transparency for all colors (0 is transparent, 1 is opaque) or a SpatRaster with values between 0 and 1 to set the transparency by cell. To set the transparency for a given color, set it to the colors directly
`sort`	logical. If `TRUE` legends with categorical values are sorted. If `x` is a `SpatVector` you can also supply a vector of the unique values, in the order in which you want them to appear in the legend
`reverse`	logical. If `TRUE`, the legend order is reversed
`grid`	logical. If `TRUE` grid lines are drawn. Their properties such as type and color can be set with the `pax` argument
`nc`	positive integer. Optional. The number of columns to divide the plotting device in (when plotting multiple layers)
`nr`	positive integer. Optional. The number of rows to divide the plotting device in (when plotting multiple layers)
`main`	character. Main plot titles (one for each layer to be plotted). You can use arguments `cex.main`, `font.main`, `col.main` to change the appearance; and `loc.main` to change the location of the main title (either two coordinates, or a character value such as "topleft"). You can also use `sub=""` for a subtitle. See `title`
`maxnl`	positive integer. Maximum number of layers to plot (for a multi-layer object).
`add`	logical. If `TRUE` add the object to the current plot
`ext`	SpatExtent. Can be use instead of xlim and ylim to set the extent of the plot
`reset`	logical. If `TRUE` add the margins (see argument `mar`) are reset to what they were before calling plot; doing so may affect the display of additional objects that are added to the map (e.g. with `lines`)
`values`	Either a vector with values to be used for plotting or a two-column data.frame, where the first column matches a variable in `x` and the second column has the values to be plotted
`...`	arguments passed to `plot("SpatRaster", "numeric")` and additional graphical arguments

Examples

 
## SpatRaster
f <- system.file("ex/elev.tif", package="terra") 
r <- rast(f)
plot(r)

plot(r, type="interval")

plot(r, plg=list(x=6.35, y = c(49.9, 50.1), title="Legend\nTitle", title.cex=0.9), 
		pax=list(side=1:4, retro=FALSE))
north(cbind(5.8, 50.1))	

d <- classify(r, c(100,200,300,400,500,600))
plot(d)

plot(d, type="interval", breaks=1:5) 
plot(d, type="interval", breaks=c(1,4,5), plg=list(legend=c("1-4", "4-5"))) 
plot(d, type="classes", xlim=c(5.6, 6.6), 
	plg=list(legend=c("Mr", "Xx", "As", "Zx", "Bb"), x="bottomleft"))


x <- trunc(r/200)
levels(x) <- data.frame(id=0:2, element=c("earth", "wind", "fire"))
plot(x, plg=list(x="topright"),mar=c(2,2,2,2))

oldpar <- par(no.readonly=TRUE)

# two plots with the same legend
dev.new(width=6, height=4, noRStudioGD = TRUE)
par(mfrow=c(1,2))
plot(r, range=c(50,600), mar=c(1,1,1,4))
plot(r/2, range=c(50,600), mar=c(1,1,1,4))

# as we only need one legend (also see the "panel" method):	
par(mfrow=c(1,2))
plot(r, range=c(50,600), mar=c(2, 2, 2, 2), plg=list(size=0.9, cex=.8), 
	pax=list(side=1:2, cex.axis=.6), box=FALSE)
#text(182500, 335000, "Two maps, one plot", xpd=NA)
plot(r/2, range=c(50,600), mar=c(2, 2, 2, 2), legend=FALSE, 
	pax=list(side=c(1,4), cex.axis=.6), box=FALSE)

par(oldpar)

# multi-layer with RGB
s <- rast(system.file("ex/logo.tif", package="terra"))   
s
plot(s)
# remove RGB
plot(s*1)
# or use layers
plot(s, 1)
plot(s, 1:3)

# fix legend by linking values and colors

x = rast(nrows = 2, ncols = 2, vals=1)
y = rast(nrows = 2, ncols = 2, vals=c(1,2,2,1))
cols = data.frame(id=1:2, col=c("red", "blue"))
plot(c(x,y), col=cols)

r  = rast(nrows=10, ncols=10, vals=1:100)
dr = data.frame(from=c(5,33,66,150), to=c(33, 66, 95,200), col=rainbow(4))
plot(r, col=dr)

### SpatVector 

f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)

plot(v)

plot(v, "NAME_2", col=rainbow(12), border=c("gray", "blue"), lwd=3)

plot(v, 2, pax=list(side=1:2), plg=list(x=6.16, y=50.17, cex=.8), xlim=c(5.7, 6.7))

plot(v, 4, pax=list(side=1:2), plg=list(x=6.2, y=50.2, ncol=2), main="", box=FALSE)
 
plot(v, 1, plg=list(x=5.8, y=49.37, horiz=TRUE, cex=1.1), main="", mar=c(5,2,0.5,0.5))

plot(v, density=1:12, angle=seq(18, 360, 20), col=rainbow(12))


plot(v, "AREA", type="interval", breaks=3, mar=c(3.1, 3.1, 2.1, 3.1),
  plg=list(x="topright"), main="")

plot(v, "AREA", type="interval", breaks=c(0,200,250,350), 
	mar=c(2,2,2,2), xlim=c(5.7, 6.75),
	plg=list(legend=c("<200", "200-250", ">250"), cex=1, bty="o", 
	x=6.3, y=50.15, box.lwd=2, bg="light yellow", title="My legend"))

terra documentation built on April 12, 2025, 1:43 a.m.