Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

How to Build an ExtJS 3.4 Scatter Chart with Logarithmic Axis

DZone's Guide to

How to Build an ExtJS 3.4 Scatter Chart with Logarithmic Axis

· Big Data Zone
Free Resource

See how the beta release of Kubernetes on DC/OS 1.10 delivers the most robust platform for building & operating data-intensive, containerized apps. Register now for tech preview.

Problem

You're rendering data that increases exponentially, and wish to display a chart with a log-scale axis.

Exponential data:

Logarithmic scale rendering of the same:

Solution

Set the “scale” property of the relevant axis to “logarithmic.”

Discussion

There does not seem to be any way to control the frequency of the major/minor tick marks other than by fixed intervals. Be careful about setting these in this chart type, as you can quickly overwhelm the browser to the point where Flash is unresponsive. It may be preferable to control the rendering using tooltips on the data points.

For further discussion of similar charts, see the ExtJS scatter chartexample and ExtJS trend line example.

Ext.onReady(function() {
Ext.chart.Chart.CHART_URL = 'ext-3.4.0/resources/charts.swf';
   var store = new Ext.data.JsonStore({
    fields: ['year', 'action'],
    data: [
        {year: 2005, action: 100000},
        {year: 2006, action: 1000000},
        {year: 2007, action: 10000000},
        {year: 2008, action: 100000000}
        ]
  });
 
  new Ext.Panel({
    width: 390,
    height: 300,
    renderTo: 'container',
    title: 'Scatter Plot - Takings by Genre',
    items: {
      xtype: 'linechart',
      store: store,
      xField: 'year',
      xAxis: new Ext.chart.NumericAxis({
        minimum: 2004,
        maximum: 2009,
        majorUnit: 1,
 
      }),
      yAxis: new Ext.chart.NumericAxis({
        labelRenderer: Ext.util.Format.usMoney,
        minimum: 10,
        maximum: 1000000000,
        scale: 'logarithmic'
      }),
      series: [{
        yField: 'action',
        displayName: 'Action',
        style: {
          lineAlpha: 0.0
        }
      }]
    }
  });
});


New Mesosphere DC/OS 1.10: Production-proven reliability, security & scalability for fast-data, modern apps. Register now for a live demo.

Topics:

Published at DZone with permission of Gary Sieling, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}