Calculate equispaced x positions.
Calculate equispaced x positions of values that have been plotted with the plot command.
tsxpos(x,xlim,nint)
x |
A vector of numeric values or a time series object created with the ts function. |
xlim |
Explicit x limits for the x positions. |
nint |
The number of intervals between x positions. |
tsxpos calculates equispaced x positions for a vector of values or a time series created with the ts command from the stats package. It assumes that the default x limits have been used in the existing plot. It adds the appropriate padding if par("xaxs") is "r". It is mainly useful when x axis labels or some other markers are to be added to a time series plot.
A plot device must be open. If the user wishes to specify explicit x limits or the number of intervals (not values), these will override the calculations from the x values.
The calculated x positions in user units.
Jim Lemon (thanks to Prof J.C. Nash for the idea)
# create a vector of numbers y<-rnorm(28) par(mfrow=c(2,1),mar=c(6,4,4,2)) plot(y,main="Plot of the values") # convert it into a time series object yt<-ts(y,start=2011,frequency=12) # don't use the default axis plot(yt,main="Plot of the time series",xaxt="n",xlab="Month") labelpos<-tsxpos(yt) # display an axis showing the months only staxlab(1,labelpos,rep(month.abb,length.out=28)) par(mfrow=c(1,1),mar=c(5,4,4,2))
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