Further reading links to supplement your studies.

• John Tukey was instrumental in developing and promoting useful, accessible ways of exploring and presenting data.  His book (Tukey, 1977), although a bit idiosyncratic, is still well worth a read. 
  Tukey, J.W. (1977) Exploratory Data Analysis. Reading, MA: Addison-Wesley.

• The book edited by Fox and Long (1990) covers the topics I have discussed in much more detail.  Fox, J. and Long, J.S. (eds) (1990) Modern Methods of Data Analysis. London: Sage.

• Tufte (1983) is a clearly written book containing much wisdom about the use and presentation of data; it encourages careful, honest and imaginative display of information and is a very interesting and informative read.
  Tufte, E.R. (1983) The Visual Display of Quantitative Information. Cheshire, CT: Graphics Press.

• The short chapter by Ellison (2001) is much more focused graphics in research (with particular emphasis on experimental work in ecology) than Tufte (1983).  Although I do not agree with everything written in Ellison (2001), I strongly recommend it, along with much of the rest of the book containing it (Scheiner and Gurevitch, 2001) ‒ even for geographers with little interest in ecology.
  Ellison, A.M. (2001) ‘Exploratory data analysis and graphic display’, pages 37–62 in S.M. Scheiner and J. Gurevitch (eds) Design and Analysis of Ecological Experiments (2nd edn). Oxford: Oxford University Press.

• Wainer (2005) and Wainer (2009) are written for a more popular (American) audience.  The 2005 book covers the history of graphical display, as well as colourful examples of its use in the modern world, and is well worth reading.  The 2009 book focuses more on the important topic of depicting uncertainty, while also extending into other areas of data presentation and interpretation. 
  Wainer, H. (2005) Graphic Discovery: a Trout in the Milk and Other Visual Adventures. Princeton, NJ: Princeton University Press.
  Wainer, H. (2009) Picturing the Uncertain World: How to Understand, Communicate, and Control Uncertainty Through Graphical Display. Princeton, NJ: Princeton University Press.

• Heer et al. (2010) is a very up-to-date article on visualization techniques, and includes interactive graphics.
  Heer, J. Bostock, M. and Ogievetsky, V. (2010) ‘A tour through the visualization zoo. A survey of powerful visualization techniques, from the obvious to the obscure’, ACM Queue, 8(5): 20–30. (With interactive graphics using the Protovis javascript library)

• Taylor (1982) provides a good introduction to error (uncertainty): how to estimate it, cope with it and report it.  Even though it is written for physicists, it is a valuable read for undergraduate geographers. Taylor also has a useful section on dealing with outliers (Chapter 6, ‘Rejection of data’).
  Taylor, J.R. (1982) An Introduction to Error Analysis. Mill Valley, CA: University Science Books.

• Although an old book, Thornes and Brunsden (1977) contains much that is still important, including a good, short section on interpreting graphs with respect to the way that physical systems operate (in Chapter 7).  Sayer (1992) provides a useful discussion of abstraction ‒ from a social science viewpoint.
  Thornes, J.B. and Brunsden, D. (1977) Geomorphology and Time. London: Methuen.

• Finally, it is very important to get at least some grasp of statistical methods.  There are numerous books dealing with this, though not many specifically focus on geography.  Crawley (2005) provides an excellent introduction to statistical techniques, starting from first principles and using the open-source statistical analysis package ‘R’, which is now the industry standard in most scientific disciplines.  This is a general book, not just for geographers, but in my opinion it is hard to find a better statistics text.
  Crawley, M.J. (2005) Statistics: An Introduction Using R. Chichester: Wiley.

• Zuur et al. (2009) provides a beginner’s guide to R, which focuses heavily on learning the extremely powerful graphing capabilities of the software.
  Zuur, A.F., Ieno, E.N. and Meesters, E.H.W.G. (2009) A Beginner’s Guide to R. New York: Springer.

• Many social sciences students just starting statistics find Pallant (2013) and the previous editions very helpful.  Rogerson (2010) has also has useful material, especially on spatial statistics.
  Pallant, J. (2013) SPSS Survival Manual: a Step by Step Guide to Data Analysis Using IBM SPSS (5th edn). Milton Keynes: Open University Press.
  Rogerson, P.A. (2010) Statistical Methods for Geography: a Student’s Guide (3rd edn). London: Sage.