Visualize This, 2nd Edition

Ch.4Visualizing Time

Businesses grow, public opinion changes, populations shift, communities evolve, user counts stagnate, and weight fluctuates. Time passes. With time series data, you can see how things change and by how much. This chapter covers different types of time-series datasets and the charts you can use, depending on what you're looking for. You look at time every day. It's on your computer, your phone, and your watch. It's in your car. It's on your calendar. Even without a clock, you feel time as you wake up and go to sleep. The sun rises, and it sets. Time moves forward, and sometimes it feels like it's standing still. If we're lucky, we get older. So, it's only natural to look at data over time.

Time-series data lets you see how things change through trends, events, and cycles.

Trends represent a shift, such as an increase or a decrease, over a range of time or specific points in time when something significant happens. When the trends and events seem to happen again and again, you start to see repeating patterns or cycles.

Some charts show these patterns better than others. You'll learn about the options in the following sections. You also get your hands dirty with R and Adobe Illustrator—two programs that go great together.

TRENDS

Are things getting better, worse, or staying the same? Is there growth or decline? Trends in data represent patterns in a certain direction. To see these patterns, you need more than a single data point. Instead, you must visualize ...