How to draw gauge chart in R?

Question

How can i draw a following plot in R?

  Red = 30
  Yellow = 40
  Green = 30 

  Needle at 52. 

Pls help me out as i am in great need.

Answer 1

Here's a very quick and dirty implementation using grid graphics

library(grid)

draw.gauge<-function(x, from=0, to=100, breaks=3, 
    label=NULL, axis=TRUE, cols=c("red","yellow","green")) {

    if (length(breaks)==1) {
        breaks <- seq(0, 1, length.out=breaks+1)
    } else {
        breaks <- (breaks-from)/(to-from)
    }
    stopifnot(length(breaks) == (length(cols)+1))

    arch<-function(theta.start, theta.end, r1=1, r2=.5, col="grey", n=100) {
        t<-seq(theta.start, theta.end, length.out=n)
        t<-(1-t)*pi
        x<-c(r1*cos(t), r2*cos(rev(t)))
        y<-c(r1*sin(t), r2*sin(rev(t)))
        grid.polygon(x,y, default.units="native", gp=gpar(fill=col))
    }
    tick<-function(theta, r, w=.01) {
        t<-(1-theta)*pi
        x<-c(r*cos(t-w), r*cos(t+w), 0) 
        y<-c(r*sin(t-w), r*sin(t+w), 0) 
        grid.polygon(x,y, default.units="native", gp=gpar(fill="grey"))
    }
    addlabel<-function(m, theta, r) {
        t<-(1-theta)*pi      
        x<-r*cos(t)
        y<-r*sin(t) 
        grid.text(m,x,y, default.units="native")
    }

    pushViewport(viewport(w=.8, h=.40, xscale=c(-1,1), yscale=c(0,1)))
    bp <- split(t(embed(breaks, 2)), 1:2)
    do.call(Map, list(arch, theta.start=bp[[1]],theta.end=bp[[2]], col=cols))
    p<-(x-from)/(to-from)
    if (!is.null(axis)) {
            if(is.logical(axis) && axis) {
            m <- round(breaks*(to-from)+from,0)
            } else if (is.function(axis)) {
            m <- axis(breaks, from, to)
            } else if(is.character(axis)) {
            m <- axis
            } else {
                   m <- character(0)
            }
        if(length(m)>0) addlabel(m, breaks, 1.10)
    }
    tick(p, 1.03)
    if(!is.null(label)) {
            if(is.logical(label) && label) {
            m <- x
            } else if (is.function(label)) {
            m <- label(x)
            } else {
            m <- label
            }
            addlabel(m, p, 1.15)
    }
    upViewport()
}

This function can be used to draw one gauge

grid.newpage()
draw.gauge(100*runif(1))

or many gauges

grid.newpage()
pushViewport(viewport(layout=grid.layout(2,2)))
for(i in 1:4) {
    pushViewport(viewport(layout.pos.col=(i-1) %/%2 +1, layout.pos.row=(i-1) %% 2 + 1))
    draw.gauge(100*runif(1))
    upViewport()
}
popViewport()

It's not too fancy so it should be easy to customize.

You can now also add a label

draw.gauge(75, label="75%")

I've added another update to allow for drawing an "axis". You can set it to TRUE to use default values, or you can pass in a character vector to give whatever labels you want, or you can pass in a function that will take the breaks (scaled 0-1) and the from/to values and should return a character value.

grid.newpage()
draw.gauge(100*runif(1), breaks=c(0,30,70,100), axis=T)