# Plotting

Need data in the right format first

Check it!!

**Load data**

data1<-read.table(“t:\\Data\\data.txt”,header=T)

This load a data.txt file to be read as a table from the t drive in folder “Data”. header=T means the top rows are the names of the columns.

This data is now attach to data

enter data1

**Getting attached**

Attach it for more semi permanent use

attach(data1) #attach data to data1

Call data by the heading names instead of data$fish you would just use fish

names(data1) #attach data1 to names

**Simple things first**

x<-1:10

y<-c(11,12,9,7,5,8,4,4,5,3)

plot(x,y)

**Add labels**

xlab is for the x axis (bottom one)

ylab is for the y axis (side one)

plot(x,y,ylab=’Response variable’,xlab=’Explanatory variable’)

**Change colour of the points**

plot(x,y,col=”red”)

**Change the points**

plot(x,y,pch=3)

http://rgraphics.limnology.wisc.edu/index.php

**Add a regression line**

abline(lm(y~x))

~ tilda

y=Response variable

x=Explanatory variable

**Draw a line**

lines(c(0,10),c(12,0),lty=2))

#draw a line when y=12 x=0 and when y=0 and x=10

**Add more data to your graph**

load new data, label it and add them as points, change the colour, point shape to show that its different

points(x1,y1,col=’green’, pch=5)

**Merge data on one graph**

plot(c(x,x1),c(y,y1),xlab=’x’,ylab=’y’,type=”n”) #plotting a blank axis but the right size

points(x,y,col=’pink’) #plot x and y data in pink

points(x1,y1,col=’green’) #plot x1 and y1 data in green

**add regression lines**

abline(lm(y~x))

abline(lm(y1~x1))

**find the ranges of the data**

range(c(x,x1)) OR range(c(y,y1))