# [R] multiple scale

From: <herodote_at_oreka.com>
Date: Wed 03 Aug 2005 - 02:18:15 EST

Hi all

i need to put on one graph 2 functions who's x axis is the same and y not.

I mean on horizontal the time, and on vertical left: pressure, on vertical right: rpm of a motor, is R able to do that?

i've found this that i could adapt maybe (i don't need time series really?) :/ :

(http://tolstoy.newcastle.edu.au/R/help/04/03/1456.html)
##
## Description: A simple function which plots two time series on one plot where
## the series can have different value intervals over the same time interval.
## Usage: ts.plot.2Axis(xleft, xright)
## Arguments: xleft is the time series for the left vertical axis and xright
## is for the right axis. xleft and xright are defined as time series with
## the 'ts' function in package ts.
## ts.plot function must be available, do library(ts) to ensure this if
## necessary.
## In addition the usual 'ts.plot' and 'plot' parameters can be set
## directly (mar, main, xlab, ylab, lwd) or through gpars as in ts.plot.
## Also parameter digits is the preferred number of decimal digits on right
## axis and ticks is the preferred number of tick marks on right axis.
## Details: The time series for the right vertical axis is scaled with a simple
## rule of thumb scaling.
## The ts.plot function is used to plot the series.
## Value: None.
## Note: When scaling is not acceptable try switching the series parameters.
## If a ylabel is to be set it is here only possible for the left axis.
## Author and date: Hauksson, Bjorn Arnar. March 2004.
## Example:
## First paste this function into the R console or use 'source'.
#library(ts)
#data(UKLungDeaths)
#x <- ldeaths
#y <- fdeaths/mdeaths
#ts.plot.2Axis(x, y)
#legTxt <- c("UK lung deaths", "UK female/male deaths (rhs)")
#legend(1976.5, 3950, legTxt, lty=c(1:2), col=c(1:2), lwd=2, bty="n")
##

ts.plot.2Axis <- function(xleft, xright, digits=1, ticks=5,

```                          mar=(c(4,4,4,4)+0.1), main="",
xlab="", ylab="", lwd=2, gpars=list()) {
# Settings for other parameters than those in the function parameter list
par(mar=mar) # Margins
k <- ncol(as.matrix(xleft)) # Number of time series on left vertical scale
lty <- c(1:(k+1)) # Line types
col <- c(1:(k+1)) # Line colors

# Scale time series on right vertical axis
scale <- (max(xleft)-min(xleft))/(max(xright)-min(xright))
xright2 <- xright*scale
meanScale <- mean(xleft) - mean(xright2)
xright2 <- xright2 + meanScale

# Plot the series
ts.plot(xleft, xright2, lty=lty, col=col, main=main, ylab=ylab, xlab=xlab,
lwd=lwd, gpars=gpars)

# Add the right vertical axis labels
lab <- seq(round(min(xright), digits), round(max(xright), digits),
length=ticks)
labAt <- seq(min(xright2), max(xright2), length=ticks)
axis(side=4, labels=lab, at=labAt)
```
}

are there a better way to plot what i want?

thks.
guillaume.

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