TIN example with Leaflet, turf.js and chroma.js (10,000 points, Leaflet1.0.0b2)

by nathansnider

HTML

<script src="https://api.mapbox.com/mapbox.js/plugins/turf/v2.0.2/turf.min.js"></script>
<script src="//cdn.rawgit.com/gka/chroma.js/master/chroma.min.js"></script>
<script src="//cdn.leafletjs.com/leaflet/v1.0.0-beta.2/leaflet.js"></script>
<link rel="stylesheet" href="//cdn.leafletjs.com/leaflet/v1.0.0-beta.2/leaflet.css">
<div id="map"></div>

CSS

html, body, #map {
      height: 100%;
      width:100%;
      padding:0px;
      margin:0px;
   } 

.info {
    padding: 6px 8px;
    font: 14px/16px Arial, Helvetica, sans-serif;
    background: white;
    background: rgba(255, 255, 255, 0.8);
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.2);
    border-radius: 5px;
}
.legend {
    text-align: left;
    line-height: 18px;
    color: #555;
}
.legend i {
    width: 18px;
    height: 18px;
    float: left;
    margin-right: 8px;
    opacity: 0.7;
}
.legend .colorcircle {
    border-radius: 50%;
    width: 15px;
    height: 15px;
    margin-top: 0px;
}

JavaScript

/////////////////////////////////////////////////////////////////////////////////////////////
//setting up the map//
/////////////////////////////////////////////////////////////////////////////////////////////

// set center coordinates
var centerlat = 34.05;
var centerlon = -118.25;

// set default zoom level
var zoomLevel = 11; 

// initialize map
var map = L.map('map').setView([centerlat,centerlon], zoomLevel);
 
// set source for map tiles
ATTR = '&copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
'<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a> | ' +
'&copy; <a href="http://cartodb.com/attributions">CartoDB</a>';

CDB_URL = 'http://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png';

// add tiles to map
L.tileLayer(CDB_URL, {attribution: ATTR}).addTo(map);

/////////////////////////////////////////////////////////////////////////////////////////////
//generating the GeoJSON objects//
/////////////////////////////////////////////////////////////////////////////////////////////

//create some GeoJSON points to be sampled (function below)
var dotcount = 10000;
var dots = make_dots(dotcount);

var maxAvg = undefined;
var minAvg = undefined;
var tin = turf.tin(dots, 'year')
for (var i = 0; i < tin.features.length; i++) {
  var properties  = tin.features[i].properties;
  properties.average = (properties.a+properties.b+properties.c)/3;
  if (minAvg === undefined && maxAvg ===undefined) {
    maxAvg = properties.average;
    minAvg = properties.average;
  } else {
    if (properties.average > maxAvg) maxAvg = properties.average;
    if (properties.average < minAvg) minAvg = properties.average;
  }
}

var avgRange = maxAvg - minAvg;

colorRamp = chroma.scale('YlGnBu');
L.geoJson(tin, {onEachFeature: onEachTri, style: tinStyle}).addTo(map);

/////////////////////////////////////////////////////////////////////////////////////////////
//styling...