Non uniform intervals in the X-axis of LineChart

Question

Hi,
I am using a Flex3 Line chart which takes data from an External XML file.
But I dont get the DataTip points correctly if i give some numeric values in the X values and
even then, the values in the X-axis starts from the "0"th position and the interval between the "0"th & 1st value (in X axis) is half of the others (shown in red bar in the attached image) and also for the last one.
How to have the uniform intervals in the X-axis so that the DataTip shows correct values as in the data?
Below is the MXML & the XML I use:
The MXML:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" width="100%" backgroundColor="0xFFFFFF" creationComplete="fetchData();">
<mx:HTTPService id="myServ" url="TempChartData.xml" fault="faultHandler(event)"/>
<mx:Script>
<![CDATA[
     import mx.controls.Alert;
     import mx.rpc.events.*;    
     import mx.controls.ToolTip;
     //Trigger the HTTPService to fetch data from the back-end
     public function fetchData():void
          myServ.send();
     public function faultHandler(event:FaultEvent):void
          Alert.show(event.fault.message);
]]>
</mx:Script>
<mx:LineChart id="myChart" width="100%" height="100%" showDataTips="true" dataProvider="{myServ.lastResult.tasks.task}">
     <mx:horizontalAxis>
          <mx:CategoryAxis id="myHorzAxis" categoryField="name" title="My Tasks"/>
     </mx:horizontalAxis>
     <mx:verticalAxis>
          <mx:LinearAxis title="My Data Values"/>
     </mx:verticalAxis>
     <mx:horizontalAxisRenderers>
          <mx:AxisRenderer axis="{myHorzAxis}" labelRotation="45"/>
     </mx:horizontalAxisRenderers>
     <mx:series>
          <mx:LineSeries id="myLineSeries1" xField="name" yField="Value">
          </mx:LineSeries>
     </mx:series>
</mx:LineChart>
</mx:Application>
TempChartData.XML
<?xml version="1.0" encoding="utf-8"?>
<tasks usl="25" lsl="-75">
    <task name="1">
        <Value>-115</Value>       
    </task>
    <task name="2">
        <Value>-112</Value>       
    </task>
    <task name="3">
        <Value>-100</Value>       
    </task>   
    <task name="4">
        <Value>0</Value>       
    </task>
    <task name="5">
        <Value>-74</Value>       
</task>
    <task name="6">
    <Value>0</Value>
    </task>
    <task name="7">
    <Value>-67</Value>
    </task>
</tasks>

Answer 1

Please do not post VIs with infinite loops (at least without informing us that they work that way)! The loop should have a stop button on the front panel wired to the stop terminal in the loop. If you use the Abort button to stop the VI, the file never gets closed.
A long time Forum participant has said that: "Using the Abort button to stop a VI is like using a tree to stop a car. It works but may have unintended consequences!"
To get the format you want after reading you need to convert the first column in the spreadsheet file from a date-time string to a numeric which can be interpretted by the graph as a timestamp. With the format you have chosen for the file it is somewhat complicated. Spend some time reading the detailed help for the timestamp and string format functions.
In the VI attached the file is read as string. The first column is separated into 7 numerical values to create a date-time record (cluster) which is then converted to a timestamp and then to DBL. The second column is converted to an array of DBL. The arrays are bundled and connected to an XY graph. The graph X-Axis is formatted as Absolute Time, AM/PM, HH:MMS. You can add the fractional seconds if you want but the scale starts to get crowded.
Also, the error out wires from the property nodes used to initialize the graphs should be wired to the loop to assure that they execute first.
Lynn
Attachments:
test_3.2.vi ‏26 KB