Chapter 18. Getting Started Making Charts
How Excel handles charts
Embedded charts versus chart sheets
The parts of a chart
Examples of each chart type
When most people think of Excel, they think of crunching rows and columns of numbers. But as you probably know already, Excel is no slouch when it comes to presenting data visually in the form of a chart. In fact, Excel is probably the most commonly used software for creating charts.
This chapter presents an introductory overview of the Excel program's charting ability.
NOTE
One of the new features in Excel 2010 is Sparklines. A Sparkline is a mini-chart that's displayed in a single cell. Because this feature is significantly different from standard charts, I devote Chapter 21 to Sparklines.
18.1. What Is a Chart?
A chart is a visual representation of numeric values. Charts (also known as graphs) have been an integral part of spreadsheets since the early days of Lotus 1-2-3. Charts generated by early spreadsheet products were quite crude, but thy have improved significantly over the years. Excel provides you with the tools to create a wide variety of highly customizable charts.
Displaying data in a well-conceived chart can make your numbers more understandable. Because a chart presents a picture, charts are particularly useful for summarizing a series of numbers and their interrelationships. Making a chart can often help you spot trends and patterns that may otherwise go unnoticed. If you're unfamiliar with the elements of a chart, see the sidebar later in this chapter, "The Parts of a Chart."
Figure 18.1 shows a worksheet that contains a simple column chart that depicts a company's sales volume by month. Viewing the chart makes it very apparent that sales were down in the summer months (June through August), but they increased steadily during the final four months of the year. You could, of course, arrive at this same conclusion simply by studying the numbers. But viewing the chart makes the point much more quickly.
Figure 18.1. A simple column chart depicts the monthly sales volume.
A column chart is just one of many different types of charts that you can create with Excel. I discuss all chart types so you can make the right choice for your data later in this chapter.
18.2. Understanding How Excel Handles Charts
Before you can create a chart, you must have some numbers — sometimes known as data. The data, of course, is stored in the cells in a worksheet. Normally, the data that a chart uses resides in a single worksheet, but that's not a strict requirement. A chart can use data that's stored in a different worksheet or even in a different workbook.
A chart is essentially an object that Excel creates upon request. This object consists of one or more data series, displayed graphically. The appearance of the data series depends on the selected chart type. For example, if you create a line chart that uses two data series, the chart contains two lines, each representing one data series. The data for each series is stored in a separate row or column. Each point on the line is determined by the value in a single cell and is represented by a marker. You can distinguish each of the lines by its thickness, line style, color, or data markers (squares, circles, and so on).
Figure 18.2 shows a line chart that plots two data series across a 12-month period. I used different data markers (squares versus circles) to identify the two series, as shown in the legend at the bottom of the chart. The chart clearly shows the sales in the Eastern Region are declining steadily, while Western Region sales are relatively constant.
A key point to keep in mind is that charts are dynamic. In other words, a chart series is linked to the data in your worksheet. If the data changes, the chart is updated automatically to reflect those changes.
After you create a chart, you can always change its type, change the formatting, add new data series to it, or change an existing data series so that it uses data in a different range.
Figure 18.2. This line chart displays two data series.
A chart is either embedded in a worksheet, or displayed on a separate chart sheet. It's very easy to move an embedded chart to a chart sheet (and vice versa).
18.2.1. Embedded charts
An embedded chart basically floats on top of a worksheet, on the worksheet's drawing layer. The charts shown previously in this chapter are both embedded charts.
As with other drawing objects (such as Shapes or SmartArt), you can move an embedded chart, resize it, change its proportions, adjust its borders, and perform other operations. Using embedded charts enables you to print the chart next to the data that it uses.
To make any changes to the actual chart in an embedded chart object, you must click it to activate the chart. When a chart is activated, Excel displays the Chart Tools context tab. The Ribbon provides many tools for working with charts.
With one exception, every chart starts out as an embedded chart. The exception is when you create a default chart by selecting the data and pressing F11. In that case, the chart is created on a chart sheet.
18.2.2. Chart sheets
When a chart is on a chart sheet, you view it by clicking its sheet tab. Chart sheets and worksheets can be interspersed in a workbook.
To move an embedded chart to a chart sheet, click the chart to select it and then choose Chart Tools 
Design 
Location 
Move Chart. Excel displays the Move Chart dialog box, shown in Figure 18.3. Select the New Sheet option and provide a name for the chart sheet (or accept Excel's default name). Click OK, and the chart is moved, and the new chart sheet is activated.
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Figure 18.3. The Move Chart dialog box lets you move a chart to a chart sheet.
When you place a chart on a chart sheet, the chart occupies the entire sheet. If you plan to print a chart on a page by itself, using a chart sheet is often your better choice. If you have many charts, you may want to put each one on a separate chart sheet to avoid cluttering your worksheet. This technique also makes locating a particular chart easier because you can change the names of the chart sheets' tabs to provide a description of the chart that it contains.
The Excel Ribbon changes when a chart sheet is active, similar to the way it changes when you select an embedded chart.
Excel displays a chart in a chart sheet in WYSIWYG (What You See Is What You Get) mode: The printed chart looks just like the image on the chart sheet. If the chart doesn't fit in the window, you can use the scroll bars to scroll it or adjust the zoom factor. You also can change its orientation (tall or wide) by choosing Page Layout 
Page Setup 
Orientation.
18.3. Creating a Chart
Creating a chart is fairly simple:
Make sure that your data is appropriate for a chart.
Select the range that contains your data.
Choose Insert
Charts and select a chart type. These icons display drop-down lists that display subtypes. Excel creates the chart and places it in the center of the window.(Optional) Use the commands in the Chart Tools contextual menu to change the look or layout of the chart or add or delete chart elements.
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Design 
Change Chart Type. In the Change Chart Type dialog box, click Set As Default Chart.18.4. Hands On: Creating and Customizing a Chart
This section contains a step-by-step example of creating a chart and applying some customizations. If you've never created a chart, this is a good opportunity to get a feel for how it works.
Figure 18.4 shows a worksheet with a range of data. This data is customer survey results by month, broken down by customers in three age groups. In this case, the data resides in a table (created by choosing Insert 
Tables 
Table), but that's not a requirement to create a chart.
NOTE
This workbook, named hands-on example.xlsx, is available on the companion CD-ROM.
18.4.1. Selecting the data
The first step is to select the data for the chart. Your selection should include such items as labels and series identifiers (row and column headings). For this example, select the range A4:D10. This range includes the category labels but not the title (which is in A1).
Figure 18.4. The source data for the hands-on chart example.
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NOTE
The data that you use in a chart need not be in contiguous cells. You can press Ctrl and make a multiple selection. The initial data, however, must be on a single worksheet. If you need to plot data that exists on more than one worksheet, you can add more series after the chart is created. In all cases, however, data for a single chart series must reside on one sheet.
18.4.2. Choosing a chart type
After you select the data, select a chart type from the Insert 
Charts group. Each control in this group is a drop-down list, which lets you further refine your choice by selecting a subtype.
For this example, choose Insert 
Charts 
Column 
Clustered Column. In other words, you're creating a column chart, using the clustered column subtype. Excel displays the chart shown in Figure 18.5.
You can move the chart by dragging any of its borders. You can also resize it by clicking and dragging in one of its corners.
18.4.3. Experimenting with different layouts
The chart looks pretty good, but it's just one of several predefined layouts for a clustered column chart.
To see some other configurations for the chart, select the chart and apply a few other layouts in the Chart Tools 
Design 
Chart Layouts group.
Figure 18.5. A clustered columns chart.
NOTE
Every chart type has a set of layouts that you can choose from. A layout contains additional chart elements, such as a title, data labels, axes, and so on. You can add your own elements to your chart, but often, using a predefined layout saves time. Even if the layout isn't exactly what you want, it may be close enough that you need to make only a few adjustments.
Figure 18.6 shows the chart after selecting a layout that adds a chart title and moves the legend to the bottom. The chart title is a text element that you can select and edit (the figure shows the generic title). For this example, Customer Satisfaction by Age Group is a good title.
Figure 18.6. The chart, after selecting a different layout.
Experiment with the Chart Tools 
Layout tab to make other changes to the chart. For example, you can remove the grid lines, add axis titles, relocate the legend, and so on. Making these changes is easy and fairly intuitive.
18.4.4. Trying another view of the data
The chart, at this point, shows six clusters (months) of three data points in each (age groups). Would the data be easier to understand if you plotted the information in the opposite way?
Try it. Select the chart and then choose Chart Tools 
Design 
Data 
Switch Row/Column. Figure 18.7 shows the result of this change. I also selected a different layout, which provides more separation between the three clusters.
NOTE
The orientation of the data has a drastic effect on the look of your chart. Excel has its own rules that it uses to determine the initial data orientation when you create a chart. If Excel's orientation doesn't match your expectation, it's easy enough to change.
The chart, with this new orientation, reveals information that wasn't so apparent in the original version. The <30 and 30–49 age groups both show a decline in satisfaction for March and April. The 50+ age group didn't have this problem, however.
Figure 18.7. The chart, after changing the row and column orientation, and choosing a different layout.
18.4.5. Trying other chart types
Although a clustered column chart seems to work well for this data, there's no harm in checking out some other chart types. Choose Design 
Type 
Change Chart Type to experiment with other chart types. This command displays the Change Chart Type dialog box, shown in Figure 18.8. The main categories are listed on the left, and the subtypes are shown as icons. Select an icon and click OK, and Excel displays the chart using the new chart type. If you don't like the result, select Undo.
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Charts group.Figure 18.8. Use this dialog box to change the chart type.
18.4.6. Trying other chart styles
If you'd like to try some of the prebuilt chart styles, select the chart and choose Chart Tools 
Design 
Chart Styles gallery. You'll find an amazing selection of different colors and effects, all available with a single mouse click.
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Themes to apply a different theme, you'll have a new selection of chart styles designed for the selected theme.Figure 18.9 shows a few different chart type options using the customer satisfaction data.
Figure 18.9. The customer satisfaction chart, using four different chart types.
18.5. Working with Charts
This section covers some common chart modifications:
Resizing and moving charts
Copying a chart
Deleting a chart
Adding chart elements
Moving and deleting chart elements
Formatting chart elements
Printing charts
NOTE
Before you can modify a chart, the chart must be activated. To activate an embedded chart, click it. Doing so activates the chart and also selects the element that you click. To activate a chart on a chart sheet, just click its sheet tab.
18.5.1. Resizing a chart
If your chart is an embedded chart, you can freely resize it with you mouse. Click the chart's border. Handles (gray dots) appear on the chart's corners and edges. When the mouse pointer turns into a double arrow, click and drag to resize the chart.
When a chart is selected, choose Chart Tools 
Format 
Size to adjust the height and width of the chart. Use the spinners, or type the dimensions directly into the Height and Width controls.
18.5.2. Moving a chart
To move a chart to a different location on a worksheet, click the chart and drag one of its borders. You can use standard cut and paste techniques to move an embedded chart. In fact, this is the only way to move a chart from one worksheet to another. Select the chart and choose Home 
Clipboard 
Cut (or press Ctrl+X). Then activate a cell near the desired location and choose Home 
Clipboard 
Paste (or press Ctrl+V). The new location can be in a different worksheet or even in a different workbook. If you paste the chart to a different workbook, it will be linked to the data in the original workbook.
To move an embedded chart to a chart sheet (or vice versa), select the chart and choose Chart Tools 
Design 
Location 
Move Chart to display the Move Chart dialog box. Choose New Sheet and provide a name for the chart sheet (or use the Excel proposed name).
18.5.3. Copying a chart
To make an exact copy of an embedded chart on the same worksheet, activate the chart, press and hold the Ctrl key, and drag. Release the mouse button, and a new copy of the chart is created.
To make a copy of a chart sheet, use the same procedure, but drag the chart sheet's tab.
You also can use standard copy and paste techniques to copy a chart. Select the chart (an embedded chart or a chart sheet) and choose Home 
Clipboard 
Copy (or press Ctrl+C). Then activate a cell near the desired location and choose Home 
Clipboard 
Paste (or press Ctrl+V). The new location can be in a different worksheet or even in a different workbook. If you paste the chart to a different workbook, it will be linked to the data in the original workbook.
18.5.4. Deleting a chart
To delete an embedded chart, press Ctrl and click the chart (to select the chart as an object). Then press Delete. When the Ctrl key is pressed, you can select multiple charts, and then delete them all with a single press of the Delete key.
To delete a chart sheet, right-click its sheet tab and choose Delete from the shortcut menu. To delete multiple chart sheets, select them by pressing Ctrl while you click the sheet tabs.
18.5.5. Adding chart elements
To add new elements to a chart (such as a title, legend, data labels, or gridlines), use the controls on the Chart Tools 
Layout tab. These controls are arranged into logical groups, and they all display a drop-down list of options.
18.5.6. Moving and deleting chart elements
Some elements within a chart can be moved: titles, legend, and data labels. To move a chart element, simply click it to select it. Then drag its border.
The easiest way to delete a chart element is to select it and then press Delete. You can also use the controls on the Chart Tools 
Layout tab to turn off the display of a particular chart element. For example, to delete data labels, choose Chart Tools 
Layout 
Labels 
Data Labels 
None.
NOTE
A few chart elements consist of multiple objects. For example, the data labels element consists of one label for each data point. To move or delete one data label, click once to select the entire element and then click a second time to select the specific data label. You can then move or delete the single data label.
18.5.7. Formatting chart elements
Many users are content to stick with the predefined chart layouts and chart styles. For more precise customizations, Excel allows you to work with individual chart elements and apply additional formatting. You can use the Ribbon commands for some modifications, but the easiest way to format chart elements is to right-click the element and choose Format from the shortcut menu. The exact command depends on the element you select. For example, if you right-click the chart's title, the shortcut menu command is Format Chart Title.
The Format command displays a stay-on-top tabbed dialog box with options for the selected element. Changes that you make are displayed immediately, but in some cases you need to deactivate the control by pressing tab to move to the next control. You can keep this dialog box displayed while you work on the chart. When you select a new chart element, the dialog box changes to display the properties for the newly selected element.
NOTE
In Excel 2007, the designers removed the ability to double-click a chart element to display the corresponding Format dialog box. In response to user complaints, double-clicking a chart element has been reinstated in Excel 2010.
Figure 18.10 shows the Format Axis dialog box, which is displayed by right-clicking the vertical axis and selecting Format Axis from the shortcut menu — or by simply double-clicking the vertical axis.
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Figure 18.10. Each chart element has a formatting dialog box. This one is used to format a chart axis.
18.5.8. Printing charts
Printing embedded charts is nothing special; you print them the same way that you print a worksheet. As long as you include the embedded chart in the range that you want to print, Excel prints the chart as it appears onscreen. When printing a sheet that contains embedded charts, it's a good idea to preview first (or use Page Layout view) to ensure that your charts do not span multiple pages. If you created the chart on a chart sheet, Excel always prints the chart on a page by itself.
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Print, Excel prints the chart on a page by itself and does If you don't want a particular embedded chart to appear on your printout, use the Properties tab of the Format Chart Area dialog box. To display this dialog box, double-click the background area of the chart. In the Properties tab of the Format Chart Area dialog box, clear the Print Object check box.
18.6. Understanding Chart Types
People who create charts usually do so to make a point or to communicate a specific message. Often, the message is explicitly stated in the chart's title or in a text box within the chart. The chart itself provides visual support.
Choosing the correct chart type is often a key factor in the effectiveness of the message. Therefore, it's often well worth your time to experiment with various chart types to determine which one conveys your message best.
In almost every case, the underlying message in a chart is some type of comparison. Examples of some general types of comparisons include
Compare item to other items. A chart may compare sales in each of a company's sales regions.
Compare data over time. A chart may display sales by month and indicate trends over time.
Make relative comparisons. A common pie chart can depict relative proportions in terms of pie "slices."
Compare data relationships. An XY chart is ideal for this comparison. For example, you might show the relationship between marketing expenditures and sales.
Frequency comparison. You can use a common histogram, for example, to display the number (or percentage) of students who scored within a particular grade range.
Identify "outliers" or unusual situations. If you have thousands of data points, creating a chart may help identify data that is not representative.
18.6.1. Choosing a chart type
A common question among Excel users is "How do I know which chart type to use for my data?" Unfortunately, this question has no cut-and-dried answer. Perhaps the best answer is a vague one: Use the chart type that gets your message across in the simplest way.
Figure 18.11 shows the same set of data plotted by using six different chart types. Although all six charts represent the same information (monthly Web site visitors), they look quite different from one another.
Figure 18.11. The same data, plotted by using six chart types.
NOTE
This workbook is available on the companion CD-ROM. The file is named six chart types.xlsx.
The column chart (upper left) is probably the best choice for this particular set of data because it clearly shows the information for each month in discrete units. The bar chart (upper right) is similar to a column chart, but the axes are swapped. Most people are more accustomed to seeing time-based information extend from left to right rather than from top to bottom.
The line chart (middle left) may not be the best choice because it seems to imply that the data is continuous — that points exist in between the 12 actual data points. This same argument may be made against using an area chart (middle right).
The pie chart (lower left) is simply too confusing and does nothing to convey the time-based nature of the data. Pie charts are most appropriate for a data series in which you want to emphasize proportions among a relatively small number of data points. If you have too many data points, a pie chart can be impossible to interpret.
The radar chart (lower right) is clearly inappropriate for this data. People aren't accustomed to viewing time-based information in a circular direction!
Fortunately, changing a chart's type is easy, so you can experiment with various chart types until you find the one that represents your data accurately, clearly, and as simply as possible.
The remainder of this chapter contains more information about the various Excel chart types. The examples and discussion may give you a better handle on determining the most appropriate chart type for your data.
18.6.2. Column
Probably the most common chart type is column charts. A column chart displays each data point as a vertical column, the height of which corresponds to the value. The value scale is displayed on the vertical axis, which is usually on the left side of the chart. You can specify any number of data series, and the corresponding data points from each series can be stacked on top of each other. Typically, each data series is depicted in a different color or pattern.
Column charts are often used to compare discrete items, and they can depict the differences between items in a series or items across multiple series. Excel offers seven column-chart subtypes.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named column charts.xlsx.
Figure 18.12 shows an example of a clustered column chart that depicts monthly sales for two products. From this chart, it is clear that Sprocket sales have always exceeded Widget sales. In addition, Widget sales have been declining over the five-month period, whereas Sprocket sales are increasing.
Figure 18.12. This clustered column chart compares monthly sales for two products.
The same data, in the form of a stacked column chart, is shown in Figure 18.13. This chart has the added advantage of depicting the combined sales over time. It shows that total sales have remained fairly steady each month, but the relative proportions of the two products have changed.
Figure 18.14 shows the same sales data plotted as a 100% stacked column chart. This chart type shows the relative contribution of each product by month. Notice that the vertical axis displays percentage values, not sales amounts. This chart provides no information about the actual sales volumes. This type of chart is often a good alternative to using several pie charts. Instead of using a pie to show the relative sales volume in each year, the chart uses a column for each year.
Figure 18.13. This stacked column chart displays sales by product and depicts the total sales.
Figure 18.14. This 100% stacked column chart display monthly sales as a percentage.
The data is plotted with a 3-D clustered column chart in Figure 18.15. The name is a bit deceptive, because the chart uses only two dimensions, not three. Many people use this type of chart because it has more visual pizzazz. Compare this chart with a "true" 3-D column chart, shown in Figure 18.16. This type of chart may be appealing visually, but precise comparisons are difficult because of the distorted perspective view.
You can also choose from column variations known as cylinder, cone, and pyramid charts. The only difference among these chart types and a standard column chart is the shape of the columns.
Figure 18.15. A 3-D column chart.
Figure 18.16. A true 3-D column chart.
18.6.3. Bar
A bar chart is essentially a column chart that has been rotated 90 degrees clockwise. One distinct advantage to using a bar chart is that the category labels may be easier to read. Figure 18.17 shows a bar chart that displays a value for each of ten survey items. The category labels are lengthy, and displaying them legibly with a column chart would be difficult. Excel offers six bar chart subtypes.
NOTE
A workbook that contains the chart in this section is available on the companion CD-ROM. The file is named bar charts.xlsx.
NOTE
Unlike a column chart, no subtype displays multiple series along a third axis. (That is, Excel does not provide a 3-D Bar Chart subtype.) You can add a 3-D look to a column chart, but it will be limited to two axes.
You can include any number of data series in a bar chart. In addition, the bars can be "stacked" from left to right.
Figure 18.17. If you have lengthy category labels, a bar chart may be a good choice.
18.6.4. Line
Line charts are often used to plot continuous data and are useful for identifying trends. For example, plotting daily sales as a line chart may enable you to identify sales fluctuations over time. Normally, the category axis for a line chart displays equal intervals. Excel supports seven line chart subtypes.
See Figure 18.18 for an example of a line chart that depicts daily sales (200 data points). Although the data varies quite a bit on a daily basis, the chart clearly depicts an upward trend.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named line charts.xlsx.
The final line chart example, shown in Figure 18.20, is a 3-D line chart. Although it has a nice visual appeal, it's certainly not the clearest way to present the data. In fact, it's fairly worthless.
A line chart can use any number of data series, and you distinguish the lines by using different colors, line styles, or markers. Figure 18.19 shows a line chart that has three series. The series are distinguished by markers (circles, squares, and diamonds) and different line colors.
Figure 18.18. A line chart often can help you spot trends in your data.
Figure 18.19. This line chart displays three series.
Figure 18.20. This 3-D line chart does not present the data very well.
18.6.5. Pie
A pie chart is useful when you want to show relative proportions or contributions to a whole. A pie chart uses only one data series. Pie charts are most effective with a small number of data points. Generally, a pie chart should use no more than five or six data points (or slices). A pie chart with too many data points can be very difficult to interpret.
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You can "explode" one or more slices of a pie chart for emphasis (see Figure 18.21). Activate the chart and click any pie slice to select the entire pie. Then click the slice that you want to explode and drag it away from the center.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named pie charts.xlsx.
Figure 18.21. A pie chart with one slice exploded.
The pie of pie and bar of pie chart types enables you to display a secondary chart that provides more detail for one of the pie slices. Figure 18.22 shows an example of a bar of pie chart. The pie chart shows the breakdown of four expense categories Rent, Supplies, Miscellaneous, and Salary. The secondary bar chart provides an additional regional breakdown of the Salary category.
The data used in the chart resides in A2:B8. When the chart was created, Excel made a guess at which categories belong to the secondary chart. In this case, the guess was to use the last three data points for the secondary chart — and the guess was incorrect.
To correct the chart, right-click any of the pie slices and choose Format Data Series. In the dialog box that appears, select the Series Options tab and make the changes. In this example, I chose Split Series by Position and specified that the Second Plot Contains the Last 4 Values in The Series.
Figure 18.22. A bar of pie chart that shows detail for one of the pie slices.
18.6.6. XY (scatter)
Another common chart type is an XY chart (also known as scattergrams or scatter plots). An XY chart differs from most other chart types in that both axes display values. (An XY chart has no category axis.)
This type of chart often is used to show the relationship between two variables. Figure 18.23 shows an example of an XY chart that plots the relationship between sales calls made (horizontal axis) and sales (vertical axis). Each point in the chart represents one month. The chart shows that these two variables are positively related: Months in which more calls were made typically had higher sales volumes.
Figure 18.23. An XY chart shows the relationship between two variables.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named xy charts.xlsx.
NOTE
Although these data points correspond to time, the chart doesn't convey any time-related information. In other words, the data points are plotted based only on their two values.
Figure 18.24 shows another XY chart, this one with lines that connect the XY points. This chart plots a hypocycloid curve with 200 data points. It's set up with three parameters. Change any of the parameters, and you'll get a completely different curve. This is a very minimalist chart. I deleted all the chart elements except the data series itself.
If this type of design looks familiar, it's because a hypocycloid curve is the basis for a popular children's drawing toy.
Figure 18.24. A hypocycloid curve, plotted as an XY chart.
18.6.7. Area
Think of an area chart as a line chart in which the area below the line has been colored in. Figure 18.25 shows an example of a stacked area chart. Stacking the data series enables you to see clearly the total, plus the contribution by each series.
Figure 18.25. A stacked area chart.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named area charts.xlsx.
Figure 18.26 shows the same data, plotted as a 3-D area chart. As you can see, it's not an example of an effective chart. The data for products B and C are obscured. In some cases, the problem can be resolved by rotating the chart or using transparency. But usually the best way to salvage a chart like this is to select a new chart type.
Figure 18.26. This 3-D area chart is not a good choice.
18.6.8. Doughnut
A doughnut chart is similar to a pie chart, with two differences: It has a hole in the middle, and it can display more than one series of data. Doughnut charts are listed in the Other Charts category.
Figure 18.27 shows an example of a doughnut chart with two series (1st Half Sales and 2nd Half Sales). The legend identifies the data points. Because a doughnut chart doesn't provide a direct way to identify the series, I added arrows and series descriptions manually.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named doughnut charts.xlsx.
Figure 18.27. A doughnut chart with two data series.
Notice that Excel displays the data series as concentric rings. As you can see, a doughnut chart with more than one series can be very difficult to interpret. For example, the relatively larger sizes of the slices toward the outer part of the doughnut can be deceiving. Consequently, you should use doughnut charts sparingly. Perhaps the best use for a doughnut chart is to plot a single series as a visual alternative to a pie chart.
In many cases, a stacked column chart for such comparisons expresses your meaning better than does a doughnut chart (see Figure 18.28).
Figure 18.28. Using a stacked column chart is a better choice.
18.6.9. Radar
Radar charts are listed in the Other Charts category. You may not be familiar with this type of chart. A radar chart is a specialized chart that has a separate axis for each category, and the axes extend outward from the center of the chart. The value of each data point is plotted on the corresponding axis.
Figure 18.29 shows an example of a radar chart. This chart plots two data series across 12 categories (months) and shows the seasonal demand for snow skis versus water skis. Note that the water-ski series partially obscures the snow-ski series.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named radar charts.xlsx.
Using a radar chart to show seasonal sales may be an interesting approach, but it's not the best. As you can see in Figure 18.30, a stacked bar chart shows the information much more clearly.
A more appropriate use for radar charts is shown in Figure 18.31. These four charts each plot a color. More precisely, each chart shows the RGB components (the contributions of red, green, and blue) that make up a color. Each chart has one series, and three categories. The categories extend from 0 to 255.
Figure 18.29. Plotting ski sales using a radar chart with 12 categories and 2 series.
Figure 18.30. A stacked bar chart is a better choice for the ski sales data.
NOTE
If you view the charts in color, you'll see that they actually depict the color that they describe. The data series colors were applied manually.
Figure 18.31. These radar charts depict the red, green, and blue contributions for each of four colors.
18.6.10. Surface
Surface charts display two or more data series on a surface. Surface charts are listed in the Other Charts category.
As Figure 18.32 shows, these charts can be quite interesting. Unlike other charts, Excel uses color to distinguish values, not to distinguish the data series. The number of colors used is determined by the major unit scale setting for the value axis. Each color corresponds to one major unit.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named surface charts.xlsx.
NOTE
A surface chart does not plot 3-D data points. The series axis for a surface chart, like with all other 3-D charts, is a category axis — not a value axis. In other words, if you have data that is represented by x, y, and z coordinates, it can't be plotted accurately on a surface chart unless the x and y values are equally spaced.
Figure 18.32. A surface chart.
18.6.11. Bubble
Think of a bubble chart as an XY chart that can display an additional data series, which is represented by the size of the bubbles. As with an XY chart, both axes are value axes (there is no category axis). Bubble charts are listed in the Other Charts category.
Figure 18.33 shows an example of a bubble chart that depicts the results of a weight-loss program. The horizontal value axis represents the original weight, the vertical value axis shows the number of weeks in the program, and the size of the bubbles represents the amount of weight lost.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named bubble charts.xlsx.
Figure 18.34 shows another bubble chart, made up of nine series that represent mouse face parts. The size and position of each bubble required some experimentation.
18.6.12. Stock
Stock charts are most useful for displaying stock-market information. These charts require three to five data series, depending on the subtype. This chart type is listed in the Other Charts category.
Figure 18.33. A bubble chart.
Figure 18.34. This bubble chart depicts a mouse.
Figure 18.35 shows an example of each of the four stock chart types. The two charts on the bottom display the trade volume and use two value axes. The daily volume, represented by columns, uses the axis on the left. The up-bars, sometimes referred to as candlesticks, are the vertical lines that depict the difference between the opening and closing price. A black up-bar indicates that the closing price was lower than the opening price.
NOTE
A workbook that contains the charts in this section is available on the companion CD-ROM. The file is named stock charts.xlsx.
Stock charts aren't just for stock price data. Figure 18.36 shows a chart that depicts the high, low, and average temperatures for each day in May. This is a high-low-close chart.
Figure 18.35. The four stock chart subtypes.
Figure 18.36. Plotting temperature data with a stock chart.
18.7. Learning More
This chapter introduced Excel charts, including examples of the types of charts that you can create. For many uses, the information in this chapter is sufficient to create a wide variety of charts.
Those who require control over every aspect of their charts can find the information they need in the next chapter. It picks up where this one left off and covers the details involved in creating the perfect chart.