Let's say you are analyzing populations of various countries using the World Population dataset in the provided workbook. This dataset produces one record containing the population for each country for each year from 1960 to 2013. Create a view similar to the one shown in the following screenshot, which shows you the change in population over time for Afghanistan and Australia. You'll notice that Country Name has been filtered and added to the Color and Label shelves.

From this visualization alone, you can make several interesting observations. The growth of the two countries' populations was fairly similar up to 1980. At that point, the population of Afghanistan went into decline until 1988 when the population of Afghanistan started to recover. At some point around 1996, the population of Afghanistan exceeded that of Australia. The gap has grown wider ever since.

While we have a sense of the two trends, they become even more obvious when we see them. Tableau offers several ways to...