leaflet-heatbin

ALPHA plugin for heatmap.js to add heatmaps to leaflet.

what?

This is an enhanced version of leaflet-heatmap that provides greater control over how data points are grouped to create a heatmap.

why?

Most heatmaps provide little control over how data is grouped beyond a pixel radius.

For many use-cases that is not enough - we often need to know exactly what data is in each cluster.

how?

This plugin provides two ways of doing this better, you can either:

1. Define the radius in meters instead of pixels; and/or
2. Define a grid of cells which are used for value binning.

cell binning example

// define options
const options = {
  heatBin: {
    enabled:     true,
    cellSizeKm:  0.25, // e.g. bin values into 250m grid cells
    maxFactor:   0.8,  // heatmap max value will be multiplied by maxFactor
    showBinGrid: false // a debugging option, plots the binning grid on the map*
    staticMax:   100   // define a fixed number to use for scale max, default false
    minThreshold: 10   // ignore heatbin cells below this value, default false
  },
  // plus any options from heatmap.js core
  radius: 20,
  useLocalExtrema: true,
  onExtremaChange: function(data) {
    console.log(data);
  },
  pane: 'myCustomPane' // name of an existing leaflet pane to add the layer to, default: 'overlayPane'
};
const layer = L.heatBin(options);
layer.setData(myData);

meter radius example

// define options
const options = {
  fixedRadius: true,
  radiusMeters: 100
};
const layer = L.heatBin(options);
layer.setData(myData);

data format

Essentially the same as vanilla heatmap.js, with the addition of an optional param: uid. When uid is specified and heatBin is enabled, a data point is only counted once per cell, per uid.

const points = [
  {
    lat:   '<lat>',
    lng:   '<lng>',
    value: 10,
    uid:   '<uid>' // optional
  }
]

install, use

npm install leaflet-heatbin --save

This plugin has external dependencies:

• heatmap.js
• turf

To use this plugin, you either need to:

• load these dependencies yourself (prior to loading leaflet-heatbin); or
• use the standalone version with dependencies bundled, in dist/leaflet-heatbin-standalone.js

public methods

|method|params|description| |---|---|---| |isActive||check if the particle layer is currently active on the map| |setData|data: {Object}|update the layer with new data object| |update||update the layer/trigger redraw| |getLatLngBounds|data: {Object}, optional|Returns leaflet LatLngBounds of supplied, or layer data| |getGridInfo||Get information about the grid used for binning|

binning?

When binning is enabled, a grid of cells is generated using turf, which is then used to cluster data points by grid cell indices.

If you're interested to see how your data is being gridded, you can set the showBinGrid to true to see the grid at work: