Using the minField property -- Flex 2.01

Some series types let you specify a minimum value for the elements drawn on the screen. For example, in a ColumnChart control, you can specify the base value of the column. To specify a base value (or minimum) for the column, set the value of the series object's minField property to the data provider field.

Setting a value for the minField property creates two values on the axis for each data point in an area; for example:

<?xml version="1.0"?>
<!-- charts/MinField.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
  <mx:Script><![CDATA[
     import mx.collections.ArrayCollection;
     [Bindable]
     public var expenses:ArrayCollection = new ArrayCollection([
        {Month:"Jan", Profit:2000, Expenses:1500, Amount:450},
        {Month:"Feb", Profit:1000, Expenses:200, Amount:600},
        {Month:"Mar", Profit:1500, Expenses:500, Amount:300}
     ]);
  ]]></mx:Script>
  <mx:Panel title="Area Chart">
     <mx:AreaChart 
        dataProvider="{expenses}" 
        showDataTips="true"
     >
        <mx:horizontalAxis>
           <mx:CategoryAxis 
                dataProvider="{expenses}" 
                categoryField="Month"
           />
        </mx:horizontalAxis>
        <mx:series>
           <mx:AreaSeries 
                yField="Profit" 
                minField="Expenses"
                displayName="Profit"
            />
        </mx:series>
     </mx:AreaChart>
  </mx:Panel>
</mx:Application>

The resulting DataTip labels the current value "high" and the minField value "low." The following example shows an AreaChart that defines the base of each column:

For an example of using the minField property to create a waterfall or cascading ColumnChart control, see Using column charts.