Heatmap Plugin

Heatmap Plugin Object

In your chart object, add another object called heatmap. In the following example, a radar chart will be used as an underlay. Use heatmap.setdata to give the plugin some data to display. Without further modification, a basic density map with a simple simple math function looks like this:

{ 
  type: 'radar',
  heatmap: {},
}
...,
var MAX = 100;
var aData = [];
zingchart.bind('zc', 'load', function() {
  var l, k, v;
  var iMaxPoints = 512;
  for (l=0;l<iMaxPoints;l++) {
    k = 5 * Math.round(((iMaxPoints-l)%355) / 5);
    v = 5 * Math.round((l%100) / 5);
    aData.push([k, v, MAX]);
  }
  zingchart.exec('zc', 'heatmap.setdata', {
    data : aData
  });    
});
https://app.zingsoft.com/demos/embed/JJBD1PIV
https://app.zingsoft.com/demos/embed/JJBD1PIV

Data

To enter data into the heatmap, use heatmap.setdata to set the data attribute. The data attribute accepts a dataset in the form of a series of arrays. Each array contains a key, value, and maximum integer provided in the following format:

data: [[key1, val1, max1], [key2, val2, max2], ..., [keyN, valN, maxN]]

The heatmap plugin supports multiple ways to arrange its data. Use the graph object and set keyScale and valScale to the scale of the underlay chart.

For the radar chart example above, the data keys lie on the k- scale, and the key values lie on the v-scale. To use the heatmap plugin with this chart, assign keyScale to scale-k and valScale to scale-v.

{
  type : 'radar',
  heatmap : {
    graph : {
      keyScale : 'scale-k',
      valScale : 'scale-v'
    }
  },
}
https://app.zingsoft.com/demos/embed/IKJ1NV5P
https://app.zingsoft.com/demos/embed/IKJ1NV5P

Heatmap Plugin- specific Properties

You can modify how your heatmap displays your data. Using different attributes, such as brushType, size, composite, and others, the data can be made to fit any style.

Brush Type

Use the brushType attribute to modify what shape the heatmap is painted with. The brushType value options include: circle and square.

{
  type : 'radar',
  heatmap : {
    brushType: 'square' //'circle'
  },
}
https://app.zingsoft.com/demos/embed/DA8T69KQ
https://app.zingsoft.com/demos/embed/DA8T69KQ

Size

Use the size attribute to modify how large each painted shape is. Enter a number, pixel, or percentage value.

{
  heatmap : {
    brushType: 'circle',
    size: '10px'
  },
}
https://app.zingsoft.com/demos/embed/88LVKOJJ
https://app.zingsoft.com/demos/embed/88LVKOJJ

Composite

Use the composite attribute to blend shapes together for the classic heatmap look (the color shifts more towards red where a greater number of stacked shapes are present). The composite value options include: true and false.

{
  heatmap : {
    brushType: 'circle',
    size: '10px',
    composite: true
  },
}
https://app.zingsoft.com/demos/embed/EGOZM359
https://app.zingsoft.com/demos/embed/EGOZM359

Blur

Use the blur attribute to increase or decrease the amount of blur that appears around each shape. Increasing this will increase the amount of surface area each shape takes up. Enter a number, pixel, or percentage value.

{
  heatmap : {
    blur: '70px'
  }
}
https://app.zingsoft.com/demos/embed/BH0PR2UJ
https://app.zingsoft.com/demos/embed/BH0PR2UJ

Further Customization

Further customize your heatmap plugin by configuring a few important features to highlight exactly what you want to display.

Alpha

With heatmap plugin charts, you'll most likely want to find a balance between the underlay and the heatmap itself. The alpha attribute causes the heatmap to become semi-transparent. Include any value between 0.0 (transparent) to 1.0 (completely solid) and make sure to place a zero before your decimal point. By default, the alpha attribute is set to 0.5.

{
  heatmap : {
    alpha: 1
  }
}
https://app.zingsoft.com/demos/embed/X7H2IZ7I
https://app.zingsoft.com/demos/embed/X7H2IZ7I

Tooltip

By default, the tooltip object displays the numerical value of each point on the heatmap.

Note: Learn more about tooltips with our Tooltips Tutorial. See more styling options on our tooltip JSON Configuration page.

{
  heatmap : {
    tooltip: {
    	decimals: 1
    }
  }
}
https://app.zingsoft.com/demos/embed/9LFYLVES
https://app.zingsoft.com/demos/embed/9LFYLVES

Live Updating

Heatmap plugins can be brought to life using window.setInterval. With a more involved math function that updates the heatmap every 15 milliseconds, you can achieve a visual look like the following:

type : 'radar',
  heatmap : {
    graph : {
      keyScale : 'scale-k',
      valScale : 'scale-v'
    },
    brushType: 'circle',
    size: '10px',
    composite: true,
    blur: '70px',
    alpha: 1
  }
}
...,
var MAX = 100;
var aData = [];
zingchart.bind('zc', 'load', function() {
  window.setInterval(function() {
      var l, k, v;
      var iMaxPoints = 512;
      if (aData.length === 0) {
          for (l=0;l<iMaxPoints;l++) {
            k = 5 * Math.round(ZC._r_(0, 355) / 5);
            v = 5 * Math.round(ZC._r_(10, 100) / 5);
            aData.push([k, v, MAX*Math.random()]);
          }
      } else {
          for (l=aData.length-1;l>=0;l--) {
            aData[l][2] = Math.min(MAX, aData[l][2] - (MAX/19) + (MAX/20)*Math.random());
            if (aData[l][2] <= 0) {
              aData.splice(l, 1);
            }
          }
          for (l=0;l<iMaxPoints-aData.length;l++) {
            k = 5 * Math.round(ZC._r_(0, 355) / 5);
            v = 5 * Math.round(ZC._r_(10, 100) / 5);
            aData.push([k, v, MAX*Math.random()]);
          }
      }
      zingchart.exec('zc', 'heatmap.setdata', {
        data : aData
      });    
  }, 15);
});
https://app.zingsoft.com/demos/embed/VGMQ7NPX
https://app.zingsoft.com/demos/embed/VGMQ7NPX

Other Chart Underlays

Most chart types can be used as underlays. The following types are compatible with the heatmap plugin: null, area, bar, boxplot, bubble-pie, bubble, bullet, calendar, funnel, gauge, piano, heatmap, line, nestedpie, pareto, radar, range, scatter, stock, venn, and waterfall.

Mixed Charts Using Null

https://app.zingsoft.com/demos/embed/A5FO1O34
https://app.zingsoft.com/demos/embed/A5FO1O34

Map Using Null

https://app.zingsoft.com/demos/embed/PUG10N1W
https://app.zingsoft.com/demos/embed/PUG10N1W

Mixed Maps Using Null

https://app.zingsoft.com/demos/embed/KXKKBDER
https://app.zingsoft.com/demos/embed/KXKKBDER