Skip to content

Instantly share code, notes, and snippets.

@awoodruff
Created May 24, 2017 03:00
Show Gist options
  • Star 1 You must be signed in to star a gist
  • Fork 3 You must be signed in to fork a gist
  • Save awoodruff/0883d211538ed05a82fd1b82bd65bf34 to your computer and use it in GitHub Desktop.
Save awoodruff/0883d211538ed05a82fd1b82bd65bf34 to your computer and use it in GitHub Desktop.
Leaflet heatmap example
<html>
<head>
<title>A Leaflet map!</title>
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.0.3/dist/leaflet.css"
integrity="sha512-07I2e+7D8p6he1SIM+1twR5TIrhUQn9+I6yjqD53JQjFiMf8EtC93ty0/5vJTZGF8aAocvHYNEDJajGdNx1IsQ=="
crossorigin=""/>
<script src="https://unpkg.com/leaflet@1.0.3/dist/leaflet.js"
integrity="sha512-A7vV8IFfih/D732iSSKi20u/ooOfj/AGehOKq0f4vLT1Zr2Y+RX7C+w8A1gaSasGtRUZpF/NZgzSAu4/Gc41Lg=="
crossorigin=""></script>
<script src="https://code.jquery.com/jquery-2.1.1.min.js"></script>
<script src="leaflet.heat.js"></script>
<style>
#map{ height: 100% }
</style>
</head>
<body>
<div id="map"></div>
<script>
// initialize the map
var map = L.map('map').setView([42.35, -71.08], 13);
// load a tile layer
L.tileLayer('http://tiles.mapc.org/basemap/{z}/{x}/{y}.png',
{
attribution: 'Tiles by <a href="http://mapc.org">MAPC</a>, Data by <a href="http://mass.gov/mgis">MassGIS</a>',
maxZoom: 17,
minZoom: 9
}).addTo(map);
map.setZoom(12);
$.getJSON("rodents.geojson",function(data){
var locations = data.features.map(function(rat) {
// the heatmap plugin wants an array of each location
var location = rat.geometry.coordinates.reverse();
location.push(0.5);
return location; // e.g. [50.5, 30.5, 0.2], // lat, lng, intensity
});
var heat = L.heatLayer(locations, { radius: 35 });
map.addLayer(heat);
});
</script>
</body>
</html>
/*
(c) 2014, Vladimir Agafonkin
simpleheat, a tiny JavaScript library for drawing heatmaps with Canvas
https://github.com/mourner/simpleheat
*/
!function(){"use strict";function t(i){return this instanceof t?(this._canvas=i="string"==typeof i?document.getElementById(i):i,this._ctx=i.getContext("2d"),this._width=i.width,this._height=i.height,this._max=1,void this.clear()):new t(i)}t.prototype={defaultRadius:25,defaultGradient:{.4:"blue",.6:"cyan",.7:"lime",.8:"yellow",1:"red"},data:function(t,i){return this._data=t,this},max:function(t){return this._max=t,this},add:function(t){return this._data.push(t),this},clear:function(){return this._data=[],this},radius:function(t,i){i=i||15;var a=this._circle=document.createElement("canvas"),s=a.getContext("2d"),e=this._r=t+i;return a.width=a.height=2*e,s.shadowOffsetX=s.shadowOffsetY=200,s.shadowBlur=i,s.shadowColor="black",s.beginPath(),s.arc(e-200,e-200,t,0,2*Math.PI,!0),s.closePath(),s.fill(),this},gradient:function(t){var i=document.createElement("canvas"),a=i.getContext("2d"),s=a.createLinearGradient(0,0,0,256);i.width=1,i.height=256;for(var e in t)s.addColorStop(e,t[e]);return a.fillStyle=s,a.fillRect(0,0,1,256),this._grad=a.getImageData(0,0,1,256).data,this},draw:function(t){this._circle||this.radius(this.defaultRadius),this._grad||this.gradient(this.defaultGradient);var i=this._ctx;i.clearRect(0,0,this._width,this._height);for(var a,s=0,e=this._data.length;e>s;s++)a=this._data[s],i.globalAlpha=Math.max(a[2]/this._max,t||.05),i.drawImage(this._circle,a[0]-this._r,a[1]-this._r);var n=i.getImageData(0,0,this._width,this._height);return this._colorize(n.data,this._grad),i.putImageData(n,0,0),this},_colorize:function(t,i){for(var a,s=3,e=t.length;e>s;s+=4)a=4*t[s],a&&(t[s-3]=i[a],t[s-2]=i[a+1],t[s-1]=i[a+2])}},window.simpleheat=t}(),/*
(c) 2014, Vladimir Agafonkin
Leaflet.heat, a tiny and fast heatmap plugin for Leaflet.
https://github.com/Leaflet/Leaflet.heat
*/
L.HeatLayer=(L.Layer?L.Layer:L.Class).extend({initialize:function(t,i){this._latlngs=t,L.setOptions(this,i)},setLatLngs:function(t){return this._latlngs=t,this.redraw()},addLatLng:function(t){return this._latlngs.push(t),this.redraw()},setOptions:function(t){return L.setOptions(this,t),this._heat&&this._updateOptions(),this.redraw()},redraw:function(){return!this._heat||this._frame||this._map._animating||(this._frame=L.Util.requestAnimFrame(this._redraw,this)),this},onAdd:function(t){this._map=t,this._canvas||this._initCanvas(),t._panes.overlayPane.appendChild(this._canvas),t.on("moveend",this._reset,this),t.options.zoomAnimation&&L.Browser.any3d&&t.on("zoomanim",this._animateZoom,this),this._reset()},onRemove:function(t){t.getPanes().overlayPane.removeChild(this._canvas),t.off("moveend",this._reset,this),t.options.zoomAnimation&&t.off("zoomanim",this._animateZoom,this)},addTo:function(t){return t.addLayer(this),this},_initCanvas:function(){var t=this._canvas=L.DomUtil.create("canvas","leaflet-heatmap-layer leaflet-layer"),i=L.DomUtil.testProp(["transformOrigin","WebkitTransformOrigin","msTransformOrigin"]);t.style[i]="50% 50%";var a=this._map.getSize();t.width=a.x,t.height=a.y;var s=this._map.options.zoomAnimation&&L.Browser.any3d;L.DomUtil.addClass(t,"leaflet-zoom-"+(s?"animated":"hide")),this._heat=simpleheat(t),this._updateOptions()},_updateOptions:function(){this._heat.radius(this.options.radius||this._heat.defaultRadius,this.options.blur),this.options.gradient&&this._heat.gradient(this.options.gradient),this.options.max&&this._heat.max(this.options.max)},_reset:function(){var t=this._map.containerPointToLayerPoint([0,0]);L.DomUtil.setPosition(this._canvas,t);var i=this._map.getSize();this._heat._width!==i.x&&(this._canvas.width=this._heat._width=i.x),this._heat._height!==i.y&&(this._canvas.height=this._heat._height=i.y),this._redraw()},_redraw:function(){var t,i,a,s,e,n,h,o,r,d=[],_=this._heat._r,l=this._map.getSize(),m=new L.Bounds(L.point([-_,-_]),l.add([_,_])),c=void 0===this.options.max?1:this.options.max,u=void 0===this.options.maxZoom?this._map.getMaxZoom():this.options.maxZoom,f=1/Math.pow(2,Math.max(0,Math.min(u-this._map.getZoom(),12))),g=_/2,p=[],v=this._map._getMapPanePos(),w=v.x%g,y=v.y%g;for(t=0,i=this._latlngs.length;i>t;t++)if(a=this._map.latLngToContainerPoint(this._latlngs[t]),m.contains(a)){e=Math.floor((a.x-w)/g)+2,n=Math.floor((a.y-y)/g)+2;var x=void 0!==this._latlngs[t].alt?this._latlngs[t].alt:void 0!==this._latlngs[t][2]?+this._latlngs[t][2]:1;r=x*f,p[n]=p[n]||[],s=p[n][e],s?(s[0]=(s[0]*s[2]+a.x*r)/(s[2]+r),s[1]=(s[1]*s[2]+a.y*r)/(s[2]+r),s[2]+=r):p[n][e]=[a.x,a.y,r]}for(t=0,i=p.length;i>t;t++)if(p[t])for(h=0,o=p[t].length;o>h;h++)s=p[t][h],s&&d.push([Math.round(s[0]),Math.round(s[1]),Math.min(s[2],c)]);this._heat.data(d).draw(this.options.minOpacity),this._frame=null},_animateZoom:function(t){var i=this._map.getZoomScale(t.zoom),a=this._map._getCenterOffset(t.center)._multiplyBy(-i).subtract(this._map._getMapPanePos());L.DomUtil.setTransform?L.DomUtil.setTransform(this._canvas,a,i):this._canvas.style[L.DomUtil.TRANSFORM]=L.DomUtil.getTranslateString(a)+" scale("+i+")"}}),L.heatLayer=function(t,i){return new L.HeatLayer(t,i)};
Display the source blob
Display the rendered blob
Raw
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment