Graphs in R
How different:
• Once drawn, you cannot erase
• Draw elements one by one
• You have a lot of control over the
presentation
The difficult part (in my opinion)
• par()
• dimension
• letter size balance
• margin balance
The tricky part
• dev.off() - just because we forget
• Close the pdf before redoing the figure
• Or use light-weight pdf viewers
• pch - point characters
Graphic parameters - par()
• Contains information on graphing
"details"
• overall letter size
• axes letter size
• label letter size
• line thickness
• font, font size
• margins (bottom, left, top, right)
• how many figures on a page (e.g., 2 by
3)
• and more!
plot.default()
• Another important default values when
plotting
• frame the graph or not
• number limits
• draw axes or not
• line types (dotted, dashed, solid,
etc.)
Most of these you don't need to touch
If you want to change
> par(mfrow=c(2,4), mar=c(4,3,3,1))
!!!REMEMBER what the value was before!!!
You don't need to change plot.default()
Instead, specify in your plots
plot()
• Most "from-scratch" kind of plotting
command
• Other plotting commands are available (not
covered here today) - Please ask Google
• What it does:
• Creates axes, labels, frame, and title,
where applicable
• If specified, draw lines or points
(data) as well
• Most useful when your graph is simple
• Still useful for complex graphs
• You can choose not to draw data with
this command, yet specify a good x-axis
range and a good y-axis range
Data drawing
• points()
• lines()
• These draw actual data alone
• Requires the base plot (frame, or
"field of drawing") already in place
Graph output file
• pdf()
• png()
• etc.
• type ?Devices to see the available
format for your OS and R version
• the way to specify the size of output
file differs among the commands; check
the help files