leaflet-webgl-heatmap
v0.2.7
Published
A Leaflet plugin for a popular WebGL Heatmap library.
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WebGL Heatmap Leaflet Plugin
A Leaflet plugin for @pyalot's webgl heatmap library.
As @pyalot explains in his post, High Performance JS heatmaps, sometimes there is a need to be able to draw hundreds of thousands of data points to a map (and not have your browser crash due to lag).
We used his library to create a WebGL alternative to Leaflet's existing heatmap plugins.
It uses the following existing options in the library:
- gradientTexture (use a PNG instead of default green to red)
- alphaRange (show transparency)
See the example
Installation
via npm:
npm install leaflet-webgl-heatmap --save
Usage
Set up your map
var base = L.tileLayer( tileURL );
var map = L.map('mapid', {
layers : [base],
center : [44.65, -63.57],
zoom: 12
});
Initialize Heatmap
var heatmap = new L.webGLHeatmap({
size: diameter-in-meters
});
OR in pixels (doesn't scale with zoom levels):
var heatmap = new L.webGLHeatmap({
size: diameter-in-pixels,
units: 'px'
});
Add Data
You should have an array of arrays in format: [[lat, lng]...]
or be explicit with the point intensities: [[lat, lng, intensity]...]
var dataPoints = [[44.6674, -63.5703, 37], [44.6826, -63.7552, 34], [44.6325, -63.5852, 41], [44.6467, -63.4696, 67], [44.6804, -63.487, 64], [44.6622, -63.5364, 40], [44.603, - 63.743, 52]];
With this you can add the whole dataset with heatmap.setData(dataPoints)
.
Add heatmap to map
map.addLayer( heatmap );
Options
- size (in meters or pixels)
- units (m or px)
- opacity (for the canvas element)
- gradientTexture (image url or image)
- alphaRange (adjust transparency by changing to value between 0 and 1)
Methods
- multiply (alter the intensity values of all points by a given number)
License
- MIT: see mit-license