legend.bubble: Legend for bubble plot
In mapplots: Data Visualisation on Maps

Description Usage Arguments Author(s) Examples

View source: R/legend.bubble.R

Draw a legend for a bubble plot (draw.bubble)

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legend.bubble(x, y = NULL, z, maxradius = 1, n = 3, round = 0, bty = "o", mab = 1.2, 
	bg = NULL, inset = 0, pch = 21, pt.bg = NULL, txt.cex = 1, 
	txt.col = NULL, font = NULL, ...)

`x, y`	the x and y co-ordinates to be used to position the legend. `x` can be a keyword (e.g. `"topleft"`). See `legend`.
`z`	either a single value representing the largest bubble, in which case `n` determines how many bubbles are displayed; or a vector of z values which will be to be shown as bubbles in the legend.
`maxradius`	the radius of the largest bubble. this should match `maxradius` in `draw.bubble`.
`n`	integer giving the number of bubbles that should be shown in the legend. Defaults to 3. Only relevant when z is a single value.
`round`	integer indicating the number of decimal places to be used in the legend.
`bty`	single character indicating the type of box to be drawn around the legend. The allowed values are "o" (the default) and "n" (no box).
`mab`	the margin around the bubble. i.e. how much space should there be between the largest bubble and the legend box. relative to the size of the bubble.
`bg`	background colour of the legend box.
`inset`	inset distance(s) from the margins as a fraction of the plot region when legend is placed by keyword.
`pch`	plotting character, i.e., symbol to use. Defaults to 21.
`pt.bg`	background (fill) color for the open plot symbols given by pch=21:25.
`txt.cex`	character expansion for the legend text.
`txt.col`	colour of the legend text.
`font`	An integer which specifies which font to use for text. See `graphical parameters`
`...`	any other arguments to be passed to `points`.

Hans Gerritsen

data(landings)
data(coast)
xlim <- c(-12,-5)
ylim <- c(50,56)
agg <- aggregate(list(z=landings$LiveWeight),list(x=landings$Lon,y=landings$Lat),sum)
basemap(xlim, ylim, main = "Gadoid landings")
draw.shape(coast, col="cornsilk")
draw.bubble(agg$x, agg$y, agg$z, maxradius=0.5, pch=21, bg="#00FF0050")
legend.bubble("topright", z=round(max(agg$z)/1000,0), maxradius=0.5, inset=0.02, bg="lightblue",
 txt.cex=0.8, pch=21, pt.bg="#00FF0050")