Put the “art” in chart with Illustrator

We are bombarded with information on a daily basis. Whether it is from newspapers, the Internet, BlackBerrys, magazines, outdoor advertising, television, or radio, we can absorb only a limited amount. At the same time, certain bits of information require a degree of focus and attention in order for us to process and really understand them.

Aware of the challenges, designers often turn to graphs or charts to present complicated information in a simpler manner. Also known as an infographic, a well-designed graph presents key data points in a visually stimulating way that quickly conveys a message to the reader (Figure 1). Graphs are often used in annual reports, business or sales presentations, and magazine or newspaper articles.

The use of graphs is a great way to communicate numeric information in a visual and graphical manner; when you use such a way to represent your data, you can turn a jumble of numbers into compelling data points. The important thing is to remember that a graph is meant to communicate information. As we’ll see in this chapter, Adobe® Illustrator® offers many ways to control a graph’s appearance, and it can be easy to get caught up in making a graph look so pretty that the reader misses its entire point.

Figure 1: In today’s fastpaced work, graphs help people visualize and digest numerical data. In this example, the percentage of teens interested in golf is highlighted. A salesperson for golf equipment might use this to bring attention to growth in that segment.

Requirements

To follow along with this article, you will need the following software:

Adobe Illustrator CS2

Prerequisite knowledge:

Basic knowledge of Illustrator CS2

The anatomy of a graph

Before we get into the specifics of creating and editing graphs, let’s first explore how Illustrator constructs them.

A graph itself can be made up of several different elements, including the chart itself, a value and category axis, and a legend. These elements are each created as individual groups so that they can be managed easily. A graph in Illustrator is a special kind of parent group that comprises the individual groups shown in Figure 2. Depending on the settings that you use, a graph can have all or just some of these groups. As long as the elements are contained by the special parent group, you can make edits to the graph data or the settings of the graph itself, and Illustrator updates the graph accordingly. However, if you remove the parent group (by choosing Object > Ungroup), the individual elements act like regular vector objects, and you can no longer edit the graph data. (See the section “Ungrouping a Graph,” later in the chapter, where we discuss under what circumstances you would want to ungroup a graph.)

Figure 2: A graph in Illustrator is made up of many different parts.

Creating a graph in Illustrator

Creating a graph in Illustrator is a two-step process. First, you specify a size for your graph (much like drawing a rectangle), and second, you specify the data for the graph.

To create a graph, choose one of the nine Graph tools in the Toolbox (Figure 3) and click once on your artboard. This brings up the Graph dialog where you must first specify the size for the graph and then click OK. Alternatively, you can click and drag with the Graph tool on the artboard to generate a size for the graph on the fly.

Figure 3: The nine different Graph tools are grouped together in the Toolbox.

The size that you specify is the area that is enclosed within the value and the category axis (or the X and Y axis). This size won’t necessarily be the final size of all of the elements in the graph because items like values and legends will appear outside of the boundaries of the two axes.
Once you’ve specified the size of your graph, Illustrator opens the Graph Data window, in which you can enter the data for your graph. Refer to the options in the “Specifying Graph Data” section for detailed information about the different settings in the Graph Data window and the different ways you can format your data.
When you’re done, click the Apply button and close the Graph Data window.

Choosing a graph type

Creating a graph in Illustrator is much like following a recipe. You take a few numbers here, a few values there, toss them together, and Illustrator produces a functional visual representation of your data. In the world of graphs, there are many different ways to present data. Illustrator has nine different ways; each of these is called a graph type.

Column graph. A column graph presents a single group of data as a series of vertical columns. This common graph type is often used to compare a range of values (Figure 4).

Figure 4: This column graph displays how many of each kind of pitch were thrown in a baseball game.
Stacked column graph. A stacked column graph presents multiple groups of data as a series of vertical columns. Multiple values are accumulated and stacked on top of each other. Stacked column graphs are used to compare a range of values and also to indicate how individual data points may have contributed to the overall totals (Figure 5).

Figure 5: This stacked column graph displays the same information as in the previous graph, only now you can also view how many of each kind of pitch were thrown for a ball or a strike.
Bar graph. A bar graph presents a single group of data as a series of horizontal bars. The bar graph type is identical to the column graph type, only it is in a horizontal format (Figure 6).

Figure 6: This bar graph also displays how many of each kind of pitch were thrown in a baseball game.
Stacked bar graph. A stacked bar graph presents multiple groups of data as a series of horizontal bars. Multiple values are cumulated and added to the ends of the bars. The stacked bar graph is identical to the bar graph type, only in a horizontal format (Figure 7).

Figure 7: This stacked bar graph displays the same information as in the bar graph, only now you can also view how many of each kind of pitch were thrown for a ball or a strike.
Line graph. A line graph presents multiple groups of data as a series of connected lines. Line graphs are often used to show continuous measurements or trends over time (Figure 8).

Figure 8: This line graph displays ticket sales across a range of several months. The graph shows growth in ticket sales over time, and the weekend games draw larger crowds.
Area graph. An area graph is similar to a line graph, only the areas created by the lines are filled in, thus offering a visual representation of volume. This presents a cumulative value of the areas as well (Figure 9).

Figure 9: This area graph displays the same data as in the previous line graph, only here you can see a total cumulative attendance of both weekday and weekend ticket sales.
Scatter graph. A scatter graph maps multiple data points as individual dots, which makes it possible to chart trends and compare non-linear data points (Figure 10).

Figure 10: This scatter graph compares the age of hitters with the number of home runs they hit. The chart shows data for three different decades, and the data reveals a peak in home runs hit by hitters between the ages of 30 and 35.
Pie graph. A pie graph presents a single group of data points as slices or wedges of a circle. Pie charts are generally used to show percentages or how a whole is broken up into individual parts (Figure 11).

Figure 11: This pie graph breaks down the type of tickets that are sold at a baseball game. You can clearly see that the majority of tickets sold are from advanced sales.
Radar graph. A radar graph, also called a web or polar graph, plots data points in a circular pattern, which reveals values with overlapping areas (Figure 12).

Figure 12: This radar graph 1st Inning compares the sales of beer and soda over the course of a nine-inning baseball game. The graph reveals that beer sales spike between the third and fifth innings, whereas soda sales peak between the seventh and ninth innings.

Specifying graph data

When you create a graph in Illustrator, you are presented with the Graph Data window, which is the life and soul of a graph (Figure 13). After all, without any data, Illustrator can’t draw a meaningful graph. If you’ve ever seen a spreadsheet before (like in Lotus 1-2-3 or Microsoft Excel), you’ll recognize the vertical columns and horizontal rows of cells where you can specify data. You can click and drag the vertical lines to adjust the width of each row. This won’t have any effect on the appearance of your graph, but it will allow you to view all of your data if they extend beyond the boundary of each cell.

Figure 13: The Graph Data window contains the values that determine how a graph is drawn.

If you’ve already created a graph and you’ve closed the Graph Data window, you can always reopen this window for further data editing. To do so, with a graph selected on your artboard, just choose Object > Graph > Graph Data; the Graph Data window will appear.

Across the top of the Graph Data window are several items. A field where you can enter data for a selected cell (to select a cell, simply click it) appears along the entire top left side. Along the top right of the window are the following six icons, which offer additional functionality:

Import Data. Illustrator allows you to import data from an external file by clicking the Import Data icon. Illustrator presents you with a system dialog box that allows you to choose a file to use. The file that you choose must be a tab-delimited text (TXT) file. Unfortunately, Illustrator does not allow you to import Excel files directly. If you have data that already exists in an Excel file, you can save the Excel file as a tab-delimited text file, which you can then import into Illustrator.
Transpose Row/Column. When you click the Transpose Row/Column icon, the data that is already entered in the Graph Data window is swapped so that rows become columns and columns become rows. This is useful for when you either enter data incorrectly, or you want to experiment with a different graph result.
Switch X/Y. When editing graph data for a scatter graph, the Switch X/Y icon allows you to swap the X and Y axis. The icon is disabled for all other graph types.
Cell Style. By default, each cell in the Graph Data window is wide enough to display 7 digits, and each value is shown with two decimal places. By clicking the Cell Style icon, you can change both the column width and the number of decimals. This setting applies to all of the cells in the Graph Data window (you can’t apply different settings to individual cells).
Revert. Clicking the Revert icon returns the graph data to the values specified when you last clicked the Apply button.
Apply. The Apply button takes the values specified in the Graph Data window and generates or updates your selected Graph.

Formatting data within the Graph Data window

Almost as important as the data itself is the way that you actually enter it into the Graph Data window. The graph type that you choose and the way in which you format the values within the cells of the Graph Data window are the two items that most impact how Illustrator draws your graph.

For example, if you just specify numeric values in the Graph Data window, Illustrator draws the graph correctly, but people who read your graph may not understand its significance. In order for a graph to be effective, a reader needs to understand what the values stand for. One way to help a reader make sense of a graph is by adding labels, which identify what a particular axis or data point represents.

In the Graph Data window, you can specify labels simply by entering the text of the labels within the cells. If Illustrator sees a value that contains letters instead of numbers, it assumes the cell contains a label, and not a numerical value that affects the graph itself (Figure 14). In order to specify a number as a numerical value, you must enclose it in quotation marks.

Figure 14: These two graphs represent the same data, but the bottom one has legend and category labels added to make the meaning of the graph immediately apparent.

Customizing graphs

Once you’ve created a graph, you can edit it and customize it to fit your needs. At any time, you can select a graph and open the Graph Data window where you can change the data. When you check the Apply button, your graph updates to reflect the new data.

However, there can be more to a graph than just the data itself. For example, a graph has a category axis, a value axis, a legend, and other elements. To make adjustments to these settings, select a graph on the artboard and choose Object > Graph > Type to open the Graph Type dialog. Depending on the type of graph that you have chosen, the Graph Type dialog offers several panels with specific options (Figure 15).

Figure 15: Illustrator offers additional settings for how graphs appear through the Graph Type dialog. Each graph type maintains options specific to its type of graph.

Utilizing graph designs

Purely from a numbers point of view, bars, lines, and squares get the point across when you’re creating a graph. However, there’s plenty of room for creativity when you’re drawing graphs as well. Sometimes, a graphic can add a really nice touch to the overall appearance of a graph, and it can even make it easier to pick up on key data points.

In Illustrator, custom art that is used instead of bars to display values in a graph is called a graph design. For the most part, graph designs behave much like patterns do. First, you define a graph design. Once defined, you can apply the graph design to a graph in your document. There are two kinds of graph designs in Illustrator: a Column graph design, which is used for drawing columns in column graphs; and a Marker graph design, which is used for drawing markers in line or scatter graphs.

Here are the steps that you need to follow to create a graph design:

Select the art on your artboard that you’d like to use as a graph design. Most Illustrator objects can be used in a graph design, with the exception of editable text or placed images—although you can use symbols.
Choose Object > Graph > Design to bring up the Graph Design dialog. Click the New Design button and then click the Rename button so that you can give your graph design a unique and recognizable name.
Click OK (Figure 16).

Figure 16: Here we’ve defined a Graph Design using a baseball that we traced and expanded.

Now that you’ve created a graph design, here are the steps you need to follow in order to apply the graph style to your graph:

Select the graph object on the artboard.
If you’re working with a column graph, choose Object > Graph > Column. From the Graph Column dialog, choose a column design and a column type (Figure 17).

(+) view larger

Figure 17: On the left is the Graph Column dialog where we used the Baseball design for the columns of the graph. On the right is the finished graph.
If you’re working with a line or scatter graph, choose Object > Graph > Marker. From the Graph Marker dialog, choose a marker and click OK.

Ungrouping a graph

At any time, you can decide to ungroup your graph, although if you do so, the graph is reduced to regular vector objects and is no longer editable as a graph object. Designers may ungroup a graph once they know the numbers won’t change anymore. Once ungrouped, a designer can edit the objects freely.

Raising the bar with graphs

You can take advantage of the graph feature in Illustrator in numerous ways. Once you’ve created a graph, you can use the Direct Selection tool to select individual parts of a graph and apply different fill or stroke attributes (by default, Illustrator generates graphs using different shades of gray). You can also apply other Illustrator features, such as Live Effects (like 3D or Scribble) or transparency. You can even use graph elements as masks for photographs.

In addition, you can use an Illustrator graph as a guide for more customized artwork. For example, you may want to create an intricate infographic using customized shapes. By creating a simple graph with real data, you can draw artwork in scale to depict numeric data in a visual way (Figure 18).

Figure 18: Graphs don’t have to be boring. Use Illustrator’s feature set and your creativity to create graphs that demand attention.

If bringing data into Illustrator isn’t your cup of tea, you can use Excel to generate a graph, which you can then save as PDF from Excel (if you have Adobe® Acrobat® installed on your computer, you should have a utility called PDFMaker available from within Microsoft Office). Once you’ve created the PDF, open it in Illustrator, where you can customize it as needed (you won’t be able to edit the graph data however).

Where to go from here

For more information about Illustrator, check out the following resources:

Put Illustrator CS2 to Work for you, by Total Training
Creating transitions with blends in Illustrator CS2, by Mordy Golding