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25_044039 ch19.qxp  11/21/06  11:10 AM  Page 377
                                             Surface charts
                                             Surface charts display two or more data series on a surface. Surface charts are listed in the Other Charts
                                             category.
                                             As Figure 19.32 shows, these charts can be quite interesting. Unlike other charts, Excel uses color to distin-
                                             guish 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.
                                                       A workbook that contains the charts in this section is available on the companion CD-ROM.
                                      ON  the  CD-ROM
                                      ON  the  CD-ROM
                                                       The file is named surface charts.xlsx.
                                                       It’s important to understand that a surface chart does not plot 3-D data points. The series axis
                                          NOTE
                                          NOTE
                                                       for a surface chart, as 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 sur-
                                             face chart unless the x and y values are equally spaced.
                                      FIGURE 19.32
                                     A surface chart.



                                             Bubble charts                                  Getting Started Making Charts    19
                                             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 19.33 shows an example of a bubble chart that depicts the results of a weight-loss program. The hor-
                                            izontal 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.
                                                       A workbook that contains the charts in this section is available on the companion CD-ROM.
                                      ON  the  CD-ROM  The file is named bubble charts.xlsx.
                                      ON  the  CD-ROM





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