Microsoft Excel 2016 BIBLE (2016)
Creating Charts and Graphics
Creating Sparkline Graphics
IN THIS CHAPTER
1. Introducing the Sparkline graphics feature
2. Adding Sparklines to a worksheet
3. Customizing Sparklines
4. Making a Sparkline display only the most recent data
A Sparkline is a small chart that's displayed in a single cell. A Sparkline allows you to quickly spot time-based trends or variations in data. Because they're so compact, Sparklines are almost always used in a group.
Although Sparklines look like miniature charts (and can sometimes take the place of a chart), this feature is completely separate from the charting feature. For example, charts are placed on a worksheet's draw layer, and a single chart can display several series of data. A Sparkline is displayed inside a cell and displays only one series of data.
See Chapter 19, “Getting Started Making Charts,” and Chapter 20, “Learning Advanced Charting,” for information about real charts.
This chapter introduces Sparklines and presents examples that demonstrate how to use them in your worksheets.
Sparklines were introduced in Excel 2010. If you create a workbook that uses Sparklines and that workbook is opened using Excel 2007 or earlier, the Sparkline cells will be empty.
All examples in this chapter are available on this book's website at www.wiley.com/go/excel2016bible. The filename is sparkline examples.xlsx.
Excel supports three types of Sparklines. Figure 22.1 shows examples of each, displayed in column H. Each Sparkline depicts the six data points to the left.
Figure 22.1 Three groups of Sparklines.
· Line: Similar to a line chart. As an option, the line can display with a marker for each data point. The first group in Figure 22.1 shows line Sparklines, with markers. A quick glance reveals that, with the exception of Fund Number W-91, the funds have been losing value over the six-month period.
· Column: Similar to a column chart. The second group in Figure 22.1 shows the same data displayed with column Sparklines.
· Win/Loss: A “binary”-type chart that displays each data point as a high block or a low block. The third group shows win/loss Sparklines. Notice that the data is different. Each cell displays the change from the previous month. In the Sparkline, each data point is depicted as a high block (win) or a low block (loss). In this example, a positive change from the previous month is a win, and a negative change from the previous month is a loss.
If the term Sparkline seems odd, don't blame Microsoft. Edward Tufte coined the term sparkline, and in his book, Beautiful Evidence (Graphics Press), he describes it as follows:
· Sparklines: Intense, simple, word-sized graphics
In the case of Excel, Sparklines are cell-sized graphics. As you see in this chapter, Sparklines aren't limited to lines.
Figure 22.2 shows some data to be summarized with Sparklines.
Figure 22.2 Data to be summarized with Sparklines.
To create Sparkline graphics, follow these steps:
1. Select the data that will be depicted (data only, not column headings);if you're creating multiple Sparklines, select all the data. In this example, start by selecting B4:M12.
2. With the data selected, choose Insert Sparklines, and click one of the three Sparkline types: Line, Column, or Win/Loss. The Create Sparklines dialog box, shown in Figure 22.3, appears.
Figure 22.3 Use the Create Sparklines dialog box to specify the data range and the location for the Sparkline graphics.
3. Specify the location for the Sparklines. Typically, you'll put the Sparklines next to the data, but that's not a requirement. Most of the time, you'll use an empty range to hold the Sparklines. However, Excel doesn't prevent you from inserting Sparklines into cells that already contain data. The Sparkline location that you specify must match the source data in terms of number of rows or number of columns. For this example, specify N4:N12 as the Location Range.
4. Click OK. Excel creates the Sparklines graphics of the type you specified.
The Sparklines are linked to the data, so if you change any of the values in the data range, the Sparkline graphic will update. Often, you'll want to increase the column width or row height to improve the readability of the Sparklines.
Most of the time, you'll create Sparklines on the same sheet that contains the data. If you want to create Sparklines on a different sheet, start by activating the sheet where the Sparklines will be displayed. Then, in the Create Sparklines dialog box, specify the source data either by pointing or by typing the complete sheet reference (for example, Sheet1A1:C12). The Create Sparklines dialog box lets you specify a different sheet for the Data Range, but not for the Location Range. Or you can just create the Sparklines on the same sheet as the data and then cut and paste the cells to a different worksheet.
Figure 22.4 shows column Sparklines for the precipitation data.
Figure 22.4 Column Sparklines summarize the precipitation data for nine cities.
Understanding Sparkline Groups
In most situations, you'll probably create a group of Sparklines — one for each row or column of data. A worksheet can hold any number of Sparkline groups. Excel remembers each group, and you can work with the group as a single unit. For example, you can select one Sparkline in a group and then modify the formatting of all Sparklines in the group. When you select one Sparkline cell, Excel displays an outline of all the other Sparklines in the group.
You can, however, perform some operations on an individual Sparkline in a group:
· Change the Sparkline's data source. Select the Sparkline cell and choose Sparkline Tools Design Sparkline Edit Data Edit Single Sparkline's Data. Excel displays a dialog box that lets you change the data source for the selected Sparkline.
· Delete the Sparkline. Select the Sparkline cell and choose Sparkline Tools Design Group Clear Clear Selected Sparklines.
Both operations are available from the shortcut menu that appears when you right-click a Sparkline cell.
You can also ungroup a set of Sparklines by selecting any Sparkline in the group and choosing Sparkline Tools Design Group Ungroup. After you ungroup a set of Sparklines, you can work with each Sparkline individually.
When you activate a cell that contains a Sparkline, Excel displays an outline around all the Sparklines in its group. You can then use the commands on the Sparkline Tools Design tab to customize the group of Sparklines.
Sizing Sparkline cells
When you change the width or height of a cell that contains a Sparkline, the Sparkline adjusts accordingly. In addition, you can insert a Sparkline into merged cells.
Figure 22.5 shows the same Sparkline, displayed at four sizes resulting from column width, row height, and merged cells. As you can see, the size and proportions of the cell (or merged cells) make a big difference in the appearance.
Figure 22.5 A Sparkline at various sizes.
Handling hidden or missing data
By default, if you hide rows or columns that are used in a Sparkline graphic, the hidden data does not appear in the Sparkline. Also, missing data (an empty cell) is displayed as a gap in the graphic.
To change these settings, choose Sparkline Tools Design Sparkline Edit Data Hidden and Empty Cells. In the Hidden and Empty Cell Settings dialog box that appears (see Figure 22.6), specify how to handle hidden data and empty cells.
Figure 22.6 The Hidden and Empty Cell Settings dialog box.
Changing the Sparkline type
As I mentioned earlier, Excel supports three Sparkline types: Line, Column, and Win/Loss. After you create a Sparkline or group of Sparklines, you can easily change the type by selecting the Sparkline and clicking one of the three icons in the Sparkline Tools Design Type group. If the selected Sparkline is part of a group, all Sparklines in the group are changed to the new type.
If you've customized the appearance, Excel remembers your customization settings for each type if you switch among Sparkline types.
Changing Sparkline colors and line width
After you've created a Sparkline, changing the color is easy. Use the controls in the Sparkline Tools Design Style group.
Colors used in Sparkline graphics are tied to the document theme. Therefore, if you change the theme (by choosing Page Layout Themes Themes), the Sparkline colors will change to the new theme colors.
See Chapter 6, “Worksheet Formatting,” for more information about document themes.
For Line Sparklines, you can also specify the line width. Choose Sparkline Tools Design Style Sparkline Color Weight.
Highlighting certain data points
Use the commands in the Sparkline Tools Design Show group to customize the Sparklines to highlight certain aspects of the data. The options are
· High Point: Apply a different color to the highest data point in the Sparkline.
· Low Point: Apply a different color to the lowest data point in the Sparkline.
· Negative Points: Apply a different color to negative values in the Sparkline.
· First Point: Apply a different color to the first data point in the Sparkline.
· Last Point: Apply a different color to the last data point in the Sparkline.
· Markers: Show data markers in the Sparkline. This option is available only for Line Sparklines.
You control the color of the highlighting by using the Marker Color control in the Sparkline Tools Design Style group. Unfortunately, you can't change the size of the markers in Line Sparklines.
Figure 22.7 shows some Line Sparklines with various types of highlighting applied.
Figure 22.7 Highlighting options for Line Sparklines.
Adjusting Sparkline axis scaling
When you create one or more Sparklines, they all use (by default) automatic axis scaling. In other words, the minimum and maximum vertical axis values are determined automatically for each Sparkline in the group, based on the numeric range of the data used by the Sparkline.
The Sparkline Tools Design Group Axis command lets you override this automatic behavior and control the minimum and maximum value for each Sparkline or for a group of Sparklines. For even more control, you can use the Custom Value option and specify the minimum and maximum for the Sparkline group.
Sparklines don't actually display a vertical axis, so you're essentially adjusting an invisible axis.
Figure 22.8 shows two groups of Sparklines. The group at the top uses the default axis settings (Automatic for Each Sparkline). Each Sparkline shows the six-month trend for the product, but there is no indication of the magnitude of the values.
Figure 22.8 The bottom group of Sparklines shows the effect of using the same axis minimum and maximum values for all Sparklines in a group.
For the Sparkline group at the bottom (which uses the same data), I changed the vertical axis minimum and maximum to use the Same for All Sparklines setting. With these settings in effect, the magnitude of the values across the products is apparent, but the trend across the months within a product is not.
The axis scaling option you choose depends upon what aspect of the data you want to emphasize.
Faking a reference line
One useful feature that's missing in the Excel implementation of Sparklines is a reference line. For example, it might be useful to show performance relative to a goal. If the goal is displayed as a reference line in a Sparkline, the viewer can quickly see whether the performance for a period exceeded the goal.
You can, however, transform the data and then use a Sparkline axis as a fake reference line. Figure 22.9 shows an example. Students have a monthly reading goal of 500 pages. The range of data shows the actual pages read, with Sparklines in column H. The Sparklines show the six-month page data, but it's impossible to tell who exceeded the goal and when they did it.
Figure 22.9 Sparklines display the number of pages read per month.
Figure 22.10 shows another approach: transforming the data such that meeting the goal is expressed as a 1 and failing to meet the goal is expressed as a –1. I used the following formula (in cell B18) to transform the original data:
Figure 22.10 Using Win/Loss Sparklines to display goal achievement.
I copied this formula to the other cells in the B18:G25 range.
Using the transformed data, I created Win/Loss Sparklines to visualize the results. This approach is better than the original, but it doesn't convey any magnitude differences. For example, you can't tell whether the student missed the goal by 1 page or by 500 pages.
Figure 22.11 shows a better approach. Here, I transformed the original data by subtracting the goal from the pages read. The formula in cell B31 is
Figure 22.11 The axis in the Sparklines represents the goal.
I copied this formula to the other cells in the B31:G38 range and created a group of Line Sparklines, with the axis turned on. I also enabled the Negative Points option so that negative values (failure to meet the goal) clearly stand out.
Specifying a Date Axis
Normally, data displayed in a Sparkline is assumed to be at equal intervals. For example, a Sparkline might display a daily account balance, sales by month, or profits by year. But what if the data isn't at equal intervals?
Figure 22.12 shows data, by date, along with a Sparklines graphic created from column B. Notice that some dates are missing, but the Sparkline shows the columns as if the values were spaced at equal intervals.
Figure 22.12 The Sparkline displays the values as if they are at equal time intervals.
To better depict the data, the solution is to specify a date axis. Select the Sparkline and choose Sparkline Tools Design Group Axis Date Axis Type. Excel displays a dialog box, asking for the range that contains the dates. In this example, specify range A2:A11. Click OK, and the Sparkline displays gaps for the missing dates (see Figure 22.13).
Figure 22.13 After specifying a date axis, the Sparkline shows the values accurately.
If a Sparkline uses data in a normal range of cells, adding new data to the beginning or end of the range does not force the Sparkline to use the new data. You need to use the Edit Sparklines dialog box to update the data range. (Choose Sparkline Tools Design Sparkline Edit Data.) But if the Sparkline data is in a column within a table (created by choosing Insert Tables Table), the Sparkline will use new data that's added to the end of the table.
Figure 22.14 shows an example. The Sparkline was created using the data in the Rate column of the table. When you add the new rate for September, the Sparkline will automatically update its Data Range.
Figure 22.14 Creating a Sparkline from data in a table.
Displaying a Sparkline for a Dynamic Range
The example in this section describes how to create a Sparkline that displays only the most recent data points in a range. Figure 22.15 shows a worksheet that tracks daily sales. The Sparkline, in merged cells E4:E5, displays only the seven most recent data points in column B. When new data is added to column B, the Sparkline will adjust to show only the most recent seven days of sales.
Figure 22.15 Using a dynamic range name to display only the last seven data points in a Sparkline.
I started by creating a dynamic range name. Here's how:
1. Choose Formulas Defined Names Define Name, specify Last7 as the Name, and enter the following formula in the Refers To field:
This formula calculates a range by using the OFFSET function. The first argument is the first cell in the range (B2). The second argument is the number of cells in the column (minus the number to be returned and minus 1 to accommodate the label in B1).
This name always refers to the last seven nonempty cells in column B. To display a different number of data points, change both instances of 7 to a different value.
2. Chose Insert Sparklines Line. The Create Sparklines dialog box appears.
3. In the Data Range field, type Last7 (the dynamic range name);specify cell E4 as the Location Range. The Sparkline shows the data in range B11:B17.
4. Add new data to column B. The Sparkline adjusts to display only the last seven data points.
Need More about Sparklines?
This chapter describes pretty much everything there is to know about Excel Sparklines. You may be left asking, “Is that all there is?” Unfortunately, yes.
The Sparklines feature in Excel certainly leaves much to be desired. For example, you're limited to three types (Line, Column, and Win/Loss). It would be useful to have access to other Sparkline types, such as a column chart with no gaps, an area chart, and a stacked bar chart. Although Excel provides some basic formatting options, many users would prefer to have more control over the appearance of their Sparklines.
If you like the idea of Sparklines — and you're disappointed by the implementation in Excel 2016 — check out some add-ins that provide Sparklines in Excel. These products provide many additional Sparkline types, and most provide many additional customization options. Search the web for Sparklines Excel, and you'll find several add-ins to choose from.