R scatter plots
Download as DOCX, PDF1 like807 views
1) The document discusses various plotting techniques in R using sample data on diamonds, including scatter plots, adjusting plot attributes like colors, symbols and sizes, adding lines and legends, fitting linear models, and 3D scatter plots. 2) Methods covered include basic scatter plots, adjusting colors of titles, axes and backgrounds, adding points with different symbols to represent years of data, customizing line types and widths, using xyplot for grouped data, and adding linear regression lines and R^2 values to plots. 3) Advanced techniques demonstrated include 3D scatter plots using the scatterplot3D package, adding density rug plots, and smoothScatter for smoothed color density representations.
![Abhik Seal: Scatter plots in R
I have taken a sample from the Diamonds data from ggplot2 package
>sample1<-diamonds[sample(nrow(diamonds),400),]
>plot(sample1$price~sample1$carat,#Y~X
main = "Relation of diamonds price and carat",# Title
xlab ="Price",ylab = "carat",# X and Y label
xaxis="i",yaxis="i",# set axis style as internal
col ="red",# Color of the dots
pch=16)#Set the plotting symbol to filled dots
The pch attribute is changed to 2 a different symbol is noticed in figure 2.
Fig 1 Fig 2
To set the plot background color to gray we use the bgargument in the par() command
>par(bg = “gray”)
Then running the plot code you will get something like in fig 3. In par() until the plotting device is closed or a
new device is initiated, the background color stays the same.
To set the background color for a the plot region a rectangle must be drawn around the plot region figure 4 The
script is given below.
plot(sample1$price~sample1$carat,type="n") # "n" so that the plotted elements are invisible.
x<-par("usr") #gets us the co-ordinates of the plot region in a vector of form c(xleft, xright, ybottom, ytop)
rect(x[1],x[3],x[2],x[4],col="gray ")
points(plot(sample1$price~sample1$carat,pch=10)](https://image.slidesharecdn.com/plot-120519195732-phpapp02/85/R-scatter-plots-1-320.jpg)
R scatter plots
- 1. Abhik Seal: Scatter plots in R I have taken a sample from the Diamonds data from ggplot2 package >sample1<-diamonds[sample(nrow(diamonds),400),] >plot(sample1$price~sample1$carat,#Y~X main = "Relation of diamonds price and carat",# Title xlab ="Price",ylab = "carat",# X and Y label xaxis="i",yaxis="i",# set axis style as internal col ="red",# Color of the dots pch=16)#Set the plotting symbol to filled dots The pch attribute is changed to 2 a different symbol is noticed in figure 2. Fig 1 Fig 2 To set the plot background color to gray we use the bgargument in the par() command >par(bg = “gray”) Then running the plot code you will get something like in fig 3. In par() until the plotting device is closed or a new device is initiated, the background color stays the same. To set the background color for a the plot region a rectangle must be drawn around the plot region figure 4 The script is given below. plot(sample1$price~sample1$carat,type="n") # "n" so that the plotted elements are invisible. x<-par("usr") #gets us the co-ordinates of the plot region in a vector of form c(xleft, xright, ybottom, ytop) rect(x[1],x[3],x[2],x[4],col="gray ") points(plot(sample1$price~sample1$carat,pch=10)
- 2. Fig 3 Fig 4 If you want to make the title as red, axis values as blue and axis labels as red then you can do this figure 5 plot(sample1$price~sample1$carat,#Y~X main = "Relation of diamonds price and carat",# Title xlab ="Price",ylab = "carat",# X and Y label xaxis="i",yaxis="i",# set axis style as internal col.main ="red",# Color of the dots col.axis="blue", col.lab="red",pch=16) Plotting point, symbols, styles and sizes I used this data (http://www.imdpune.gov.in/ncc_rept/RESEARCH%20REPORT%202.pdf ) from the year 1999 to 2003 and the months from jan to December to plot yearly rainfall. NB: Columns are years and rows are months. Here is the code plot(rain$Year1999 ,main="Yearly Rainfall in India",xlab="Month of the Year",ylab="rainfall",pch=1) points(rain$Year2000,pch=2) points(rain$Year2001,pch=3) points(rain$Year2002,pch=4) points(rain$Year2003,pch=5) legend('top',legend=c("1999","2000","2001","2002","2003"),ncol=5,cex=0.9,bty="n",pch=1:5) Lines format can also be plotted using the lty and lwd arguments in the plot plot(rain$Year1999 ,main="Yearly Rainfall in India",xlab="Month of the Year",ylab="rainfall(mm)",type="l",lty=1,lwd=2,ylim=c(0,400)) lines(rain$Year2000,lty=2,lwd=2) lines(rain$Year2001,lty=3,lwd=2) lines(rain$Year2002,lty=4,lwd=2) lines(rain$Year2003,lty=5,lwd=2) legend('topright',legend=c("1999","2000","2001","2002","2003"),ncol=5,cex=0.9,bty="n",lty=1:5,lwd=2)
- 3. Lines type code: 0: blank 1: solid (default) 2: dashed 3: dotted 4: dotdash 5: longdash 6: twodash axis(1,at=1:length(rain$Month),labels=rain$Month) lines(rain$Year2000,col="red",type="b",lwd=2) lines(rain$Year2001,col="orange",type="b",lwd=2) lines(rain$Year2002,col="purple",type="b",lwd=2) lines(rain$Year2003,col="yellow",type="b",lwd=2) legend('topright',legend=c("1999","2000","2001","2002","2003"),col= c("black","red","orange","purple","yellow"),ncol=2,cex=0.9,bty="n",lty=1:5,lwd=2) Using xyplot to plot data. I have used the sample1 data from the diamonds dataset . You also require the lattice package for plotting.You can also plot high quality plots using ggplot see my qplot tutorial at slideshare. xyplot(price~carat,data=sample1,groups=color,auto.key=list(corner=c(1,1))) The auto.key use to make a legend at the corner of the plot.
- 4. Fitting linear model lines using lm() and abline() plot(sample1$price~sample1$carat) lmfit<-lm(sample1$price~sample1$carat) abline(lmfit,col='red') legend("topright", bty="n", legend=paste("R2 is", format(summary(lmfit)$adj.r.squared, digits=4)))# putting the R square in the plot. library(scatterplot3d) scatterplot3d(x=sample1$carat,y=sample1$depth,z=sample1$price,xlab="carat",ylab="depth",zlab="price")#fig scatterplot3d(x=sample1$carat,y=sample1$depth,z=sample1$price,xlab="carat",ylab="depth",zlab="price",pch =16,highlight.3d=TRUE,angle=45,type="h")
- 5. More on the scatterplot3d at http://www.jstatsoft.org/v08/i11/paper >plot(sample1$price~sample1$carat) >rug(sample1$carat) >rug(sample1$price,side=2,col="blue",ticksize=0.02) The rug function adds a set of lines just above the x and y axis.The closely packed lines represent the density of the data.The side argument takes four values,1: bottom axis (default) ,2: left ,3: top ,4: right.The size of the tick marks are adjusted by ticksize. smoothScatter :smoothScatter() function produces a smoothed color density representation of the scatter plot, obtained through a kernel density estimate. Lab.palette<-colorRampPalette(c("blue","red"), space = "Lab") smoothScatter(sample1$price~sample1$carat,colramp = Lab.palette)