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Fortunately, the information booth has another representation of the same data. It’s the Washington, D.C. subway map, and it shows all the stations in order on different lines, each in a different color. It also shows where each line intersects so that you can easily figure out where to switch lines. All of a sudden, navigating the Metro is easy.
The subway map doesn’t just give you data—it gives you knowledge.
Not only do you know which line to take, but you know roughly how long it’ll take to get to your destination. Without much thought, you can see that there are eight stops to your destination, stops that are a few minutes apart each, so it’ll take a bit more than 20 minutes to get from where you are to, say, the Air and Space Museum. Not only that but you can recognize each of the lines on the Metro not just by the name or final destination, but by the color as well: red, blue, yellow, green, or orange. Each line has a distinct color that you can recognize on the map—and on the walls of the metro when you’re trying to find the right line.
This simple example illustrates the compelling nature of visualization. With a mix of color, layout, markings, and other elements, a visualization can show us in a few seconds what plain numbers or text might take minutes or hours to convey, if we can draw a conclusion from them at all.
To put things in perspective, the Washington, D.C. Metro has a mere 86 sta- tions. The Tokyo subway, which consists of the Tokyo Metro and the Toei, has some 274 stations. Counting all of the railway networks in the greater Tokyo area, there are some 882 stations in total.2 That number of stations would be
virtually impossible to navigate without a map.
Trend Spotting
If you’ve ever used a spreadsheet, you’ve experienced first-hand how hard it can be to spot trends in a mass of number-filled cells. Table 5-1 is an example of U.S. Census Data on just the county of Alameda, California from 2010.
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Unlike in the move The Matrix, where numbers look like images and images look like numbers, spreadsheets aren’t quite as easy to interpret. That’s one reason programs like Microsoft Excel and Apple Numbers come with built-in capabilities for creating charts. That census data shown in Table 5-1 is a lot eas- ier to understand when we see it in graphical form, as shown in Figure 5-1.
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When we see a graph like a pie or bar chart, it’s often a lot easier to see how things are changing over time or on a relative basis.
How things change over time is critical when making decisions. A single data point, by itself, is often insufficient to tell you how things are going, regardless of whether you’re looking at sales trends or health data.
Figure 5-2 shows the U.S. Census Bureau data on new home sales starting in the year 2000. If we were to look just at the value for January 2000, which is 873,000, that wouldn’t tell us much by itself. But when we look at new home sales over time, the story is crystal clear. We can see just how dramatic a dif- ference there was between new home sales at the peak of the housing bubble and new homes sales today.3
3Chart generated via www.census.gov. The actual query is https://www.census.gov/
econ/currentdata/dbsearch?program=RESSALES&startYear=2000&endYear=2014& categories=ASOLD&dataType=TOTAL&geoLevel=US&adjusted=1&submit=GET+DATA.
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Using this kind of visual trend analysis is a key way to understand data. Investors, for example, often evaluate a company’s performance over time. A company might report revenue and profits for a given quarter. Without a view of financial performance during previous quarters, investors might conclude that the company is doing well.
But what that moment-in-time data can’t tell the investors is that the com- pany’s sales have been growing less and less each quarter. So while sales and profits in the abstract seem to be good, in reality, the company will be headed for bankruptcy if it doesn’t find a way to increase profits.
Internal context is one of the key indicators managers and investors use to figure out how business is trending. Managers and investors also need external context, which tells them how they’re doing relative to others.
Suppose that sales are down for a given quarter. Managers might conclude that their company isn’t executing well. In reality, however, sales might be off due to larger industry issues—for example, fewer homes being built in the case of real estate or less travel, in the case of the airline industry. Without external context, that is, data on how other companies in their industry did over the same time period, managers have very little insight into what’s really causing their business to suffer.
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Even when managers have both internal and external context, it’s still hard for them to tell what’s going on just by looking at numbers in the abstract. That’s where visualizations can really help.
The Many Types of Visualizations
Nearly every business user is familiar with the well-known pie chart, bar chart, or line graph. These forms of visualization are just the tip of the iceberg when it comes to converting data into its visual equivalent. There are many other types of visualizations as well.
Geographic visualizations are useful for displaying location information. Geographic visualizations often have additional information layered into them. For example, they can show population densities, store locations, income dis- tributions, weather patterns, and other kinds of data that are helpful to see on a visual basis. Figure 5-3 combines geographic information (a map of the United States) with weather data to illustrate just how much of the country is suffering from drought as of August, 2014.4
Figure 5-3. A visualization that combines geographic and weather data
4http://www.ncdc.noaa.gov/news/us-drought-monitor-update-august-5-2014 Produced
by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration.
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Maps can show routing information, telling sales people which locations to visit and when or showing drivers the optimal route to take from one loca- tion to another.
Network diagrams show connections and interconnections. Network dia- grams can illustrate the way information flows in an organization by showing the relationships between people. Network diagrams can also show connec- tions in a social network or connections between different machines in a computer network.
Time series visualizations illustrate how things change over time. A time series chart might show the consumption of natural resources such as gas, oil, and coal over a period of many years. Or it could show sources of revenue. Time series visualizations can be combined with geographic visualizations to show how the density of populations, or the earning power of certain populations, changes over time.
Infographics are frequently used for marketing purposes, and they don’t just show data in visual form but they also incorporate drawings, text, and graphics that tell a story about the data.
Word maps, like the one shown in Figure 5-4, are useful ways to visualize the most frequently mentioned words in large quantities of text.5 Such visualiza-
tions make it easy to determine what a particular body of text is all about. You can create word maps using a variety of tools. One easily accessible web tool is called Wordle, located at wordle.net.
Figure 5-4. A word map of the Constitution of the United States
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More and more visualizations are being created that are dynamic in nature. Rather than the static, fixed visualizations of the past, today’s interactive visu- alizations enable you to interact with them so that you can change the time period viewed, zoom in on certain geographic areas for more detail, or change the combinations of variables included in the visualizations to look at the data in a different way. Interactive visualizations combine the best characteristics of tra- ditional visualizations—the power of seeing data presented in graphical form— with access to modern, dynamic analytical capabilities that are easy to use.
Note
■ Many sites now showcase the incredible range of visualizations being created on a daily basis. Two such sites are visualizing.org and www.informationisbeautiful.net. The visualizations on these sites can serve as an excellent source of inspiration for creating your own compelling visualizations.
How to Create Visualizations
A number of easy-to-use tools are available to help you create your own visualizations. Visualization tools are available both online and in desktop and mobile versions. Google Public Data Explorer is one great way to get started with creating visualizations. Available at https://www.google.com/public- data/directory, the Public Data Explorer comes loaded with lots of differ- ent types of publicly available data. Without installing any software, you can experiment with a variety of different visualizations and view changes in vari- ous data sets over time.
There are also online tools available for creating specific types of visualizations. CartoDB (cartodb.com), for example, is a useful tool for creating geographic visualizations. Using CartoDB, it is easy to embed interactive visualizations of complex geographic data sets into your web site, blog, or other application with just a few lines of code.
If you’re building your own application, HighCharts (www.highcharts.com) is another visualization resource available online. With very few lines of code, you can load online data into HighCharts and it will do the hard work of dis- playing that data in chart form.
Due to compliance, privacy, or security requirements, you won’t always be able to upload data to a cloud-based visualization tool. In that case, you can use a desktop software application like Tableau Desktop or QlikTech’s QlikView. If you need to access data stored in a data repository like Hadoop, Microsoft SQL Server, Oracle, Teradata, or other data sources, you can use Tableau and QlikView to connect directly to these data sources.
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These programs can also connect to file-based data sources like Excel files and text files. This means you can access a wide range of different data sources, as well as data sources stored in multiple data repositories, and easily visualize the data contained there.
Software like Tableau Desktop (see Figure 5-5) makes it extremely easy to switch between different kinds of visualizations. That means you can take com- plex data sets and try out a variety of visualizations quickly to see which one presents your data in the most compelling manner.
Figure 5-5. The Show Me popup in Tableau Desktop allows users to switch easily between different kinds of visualizations (Courtesy Tableau Software; used with permission)
As you can see in Figure 5-6, with the right tool, it’s easy to take otherwise hard to interpret data like a sales forecast and view that in compelling, visual form.
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Regardless of the tool you choose, visualizations make complex data easy to understand. You can not only use visualizations in your presentations, but you can also embed them directly into web sites and applications.
Using Visualization to Compress Knowledge
As the saying goes, a picture is worth a thousand words. But that begs the question of why visualization is so powerful. As visualization expert David McCandless puts it, “visualization is a form of knowledge compression.”6 One
form of compression is reducing the size of the data, say by representing a word or a group of words using shorthand, such as a number. But while such compression makes data more efficient to store, it does not make data easier to understand.
A picture, however, can take a large quantity of information and represent it in a form that’s easy to understand. In Big Data, such pictures are referred to as visualizations.
Subway maps, pie charts, and bar graphs are all forms of visualization. Although visualization might seem like an easy problem at first, it’s hard for a few rea- sons. First, it’s frequently hard to get all the data that people want to visualize
Figure 5-6. Sample sales forecast data shown in Tableau Desktop with a corresponding visualization shown to the right (Courtesy Tableau Software; used with permission)
6https://www.ted.com/talks/david_mccandless_the_beauty_of_data_
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into one place and in a consistent format. Internal and external context data might be stored in two different places. Industry data might be in a market research report while actual company sales data may be stored in a corpo- rate database.
Then, the two forms of data might come in slightly different formats. Company sales data might be stored on a daily basis while industry data might be avail- able only on a quarterly basis.
Alternatively, the names given to particular pieces of data might be different; a hard drive might be referred to as “hard drives” in an industry report but referred to by model number in an internal sales database. Such forms of data inconsistency can make it hard to understand what the data is really telling us. There is no silver bullet solution to data inconsistency issues, but newer products like Trifacta and others are emerging to make the problem easier to address.
Tip
■ There remains an large opportunity to build an easy-to-use hosted data-cleansing service. Today many data consistency issues consume time that data analysts might otherwise apply to solving business problems. A hosted data cleansing and data consistency service could solve this problem on a large scale using a combination of algorithmic and human approaches.
The good news is that modern visualization products can connect directly to a variety of data sources, from local files to databases to data stores like Hadoop. By taking all that data and creating a picture of it, the data can become more than data. It can become knowledge that we can act on.
Visualization is a form of knowledge compression because a seemingly simple image can take vast amounts of structured or unstructured data and com- press it into a few lines and colors that communicate the meaning of all that data quickly and efficiently.
Why Is Visual Information So Powerful?
When it comes to visualization, few people have had as big an impact on the field as Edward Tufte. The New York Times called Tufte the “Leonardo da Vinci of data.”
In 1982, Tufte published one of the defining books of the 20th century, Visual Display of Quantitative Information. Although he began his career teaching courses on political science, Tufte’s life work has been dedicated to under- standing and teaching information design.
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One of Tufte’s contributions is a focus on making every piece of data in an illustration matter, and excluding any data that isn’t relevant. Tufte’s images don’t just communicate information; many consider his graphics to be works of art. Visualizations are not only useful as business tools, Tufte demonstrates, they can also communicate data in a visually appealing way.
Although it may be difficult to match some of the graphical approaches that Tufte popularized, infographics, as they are now commonly known, have become popular ways to communicate information.
Infographics don’t just look good. As with other aspects of Big Data, there is a scientific explanation for what makes visual representations of data so compelling.
In a blog post, Tufte cites a press release about an article published in Current Biology that describes just how much information we visually absorb.7 According
to the article, researchers at the University of Pennsylvania School of Medicine estimated that the human retina “can transmit visual input at about the same rate as an Ethernet connection.”8
For their study, the researchers used an intact retina from a guinea pig com- bined with a device called a multi-electrode array that measured spikes of electrical impulses from ganglion cells. Ganglion cells carry information from the retina to the brain. Based on their research, the scientists were able to estimate how fast all the ganglion cells—about 100,000 in total—in a guinea pig retina transmit information. The scientists were then able to calculate how much data the corresponding cells in a human retina transmitted per second. The human retina contains about one million ganglion cells. Put all those cells together and the human retina transmits information at about 10 megabits per second.
To put that in context, Tor Norretranders, a Danish popular science author, created a graphic illustrating the bandwidth of our senses. In the graphic he showed that we receive more information visually than through any of our other senses. If we receive information via sight at about the same rate as a computer network, we receive information through touch at about one tenth that rate, about the rate that a USB key interfaces with a computer.
We receive information through our ears and nose at an even slower rate, about one tenth of that of touch or about the same speed at which a hard drive interfaces with a computer; and we receive information through our taste buds at a slower rate still.
7http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0002NC. 8http://www.eurekalert.org/pub_releases/2006-07/uops-prc072606.php.
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