A pie chart consists of a circle (PIE) that is divided into two or more sectors (blocks or wedges). Pie charts emphasize the relative relationship between data and the whole, and are particularly useful in showing proportions and ratios. When data is made up of several large categories (3 to 7 categories), pie charts are most efficient to use, and too many categories can result in the splitting of pie charts into too many small chunks, which makes the interpretation of the data difficult.
Control pie chart
If you have a list of human avian influenza cases by country, in which the order of the first virus is detected in chronological order (from 1997 to 2005 December), the sequence of wedges in the pie chart is the same as the order of the countries in the table (counterclockwise):
If you want the wedges in the chart to be sorted in order from large to small, set the sort field to Cases and the sort type to descending. The default Label field is < No, but to display the name of the country/region instead, you can set the label fields to the Country text field (see left). In addition, if you want the wedge to be sorted alphabetically by country name, you can set the sort field to "country" (right).
Selection on a pie chart
You can select only one wedge on the pie chart. You cannot dynamically select multiple adjacent wedges by using a marquee or by shift+-click action. The selection point is based on the cursor position when the mouse is released.
- Since the pie chart has no axes, all of the settings in the pie axis attribute have no effect.
- Pie charts are generally not suitable for displaying negative values. A bar chart is more suitable for displaying negative values because negative values can be represented by bars that are perpendicular to the horizontal baseline. If a negative value is used in the input data of a pie chart, its absolute value is used in the pie chart.
Steps:
- Click the View menu, point to Chart, and then click Create Chart.
- Click the chart Type drop-down arrow and select a pie chart type.
- Click the Layer/Table drop-down arrow and select the Layer or table that contains the data values that you want to plot as a chart.
- Click the Value field drop-down arrow and select the field to be plotted as the value of the chart. The wizard displays the initial version of the chart. The wedge in the diagram initially renders the first data value as a starting point, and then draws the subsequent wedge in a counterclockwise direction to represent the subsequent value.
- Sort the wedges in ascending or descending order by another field by using the sort field parameter.
- Specify a different field in the callout field to label the wedge in the chart, usually as a text (string) field.
- By default, the value of the input data is added to the legend of the chart. Uncheck the Add to legend check box to disable this feature.
- Select the show labels (marks) check box to see the individual wedges in the pie chart that are labeled as actual values. If the size of the wedges is similar, it may not be easy to see their small differences, in which case this option will be used.
- You can use the color control to change the color of the wedge in the chart.
- To create an incomplete circle instead of a full circle for a pie chart, you can reduce the default setting for the total pie angle to another value of 360°.
- Use the Rotate pie chart control to adjust the start point of the pie chart from the default three o'clock position to another location in degrees.
- Use the largest portion of a split (%) Control to highlight the largest slice of a pie chart.
- Uncheck the Show borders check box to remove the pie chart and the outline of all wedges.
- Click Next to go to the general Properties page to finish drawing the chart.
ArcGIS Tutorial: Creating a Pie chart
