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Last active September 30, 2022 02:36
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How to create an interactive heatmap with Leaflet.js
Raw
index.html
<html>
<head>
<title>How to create an interactive heatmap with Leaflet.js</title>
<meta charset="utf-8">
<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css" />
<script src="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js"></script>
<script src="leaflet-heat.js"></script>
<style type="text/css">
html, body, #map{
height: 100%;
padding: 0;
margin: 0;
}
</style>
</head>
<body>
<div id="map"></map>
<script type="text/javascript">
var map = L.map('map', {doubleClickZoom: false})
.setView([
35.10418,
-106.62987],
10);
L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {attribution: 'OSM'})
.addTo(map);
var points = [];
var heat = L.heatLayer(points, {
maxZoom: 10
})
.addTo(map);
function addpoint(e){
heat.addLatLng(e.latlng);
}
map.on('click', addpoint);
</script>
</body>
</html>
Raw
leaflet-heat.js
/*
(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)};
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