This is a simple setup of Leaflet (via Mapbox) with d3 to show dots on a map. This can serve as a base for many interesting geographically based visualizations
Nice overview of using d3 + Leaflet. I found this slightly simpler to use than Mike's classic post.
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<head>
<meta charset="utf-8">
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script src='https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.js'></script>
<link href='https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.css' rel='stylesheet' />
<style>
body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
#map {
position:absolute;
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<div id="map"></div>
<script>
L.mapbox.accessToken = 'pk.eyJ1IjoiZW5qYWxvdCIsImEiOiJjaWhtdmxhNTIwb25zdHBsejk0NGdhODJhIn0.2-F2hS_oTZenAWc0BMf_uw'
//Setup our Leaflet map using Mapbox.js
var map = L.mapbox.map('map', 'mapbox.pencil', {maxZoom: 18, minZoom: 14})
.setView([51.5119112,-0.10000], 15);
// Setup our svg layer that we can manipulate with d3
var svg = d3.select(map.getPanes().overlayPane)
.append("svg");
var g = svg.append("g").attr("class", "leaflet-zoom-hide");
function project(ll) {
// our data came from csv, make it Leaflet friendly
var a = [+ll.lat, +ll.lon];
// convert it to pixel coordinates
var point = map.latLngToLayerPoint(L.latLng(ll))
return point;
}
d3.csv("dots.csv", function(err, data) {
var dots = g.selectAll("circle.dot")
.data(data)
dots.enter().append("circle").classed("dot", true)
.attr("r", 1)
.style({
fill: "#0082a3",
"fill-opacity": 0.6,
stroke: "#004d60",
"stroke-width": 1
})
.transition().duration(1000)
.attr("r", 6)
function render() {
// We need to reposition our SVG and our containing group when the map
// repositions via zoom or pan
// https://github.com/zetter/voronoi-maps/blob/master/lib/voronoi_map.js
var bounds = map.getBounds();
var topLeft = map.latLngToLayerPoint(bounds.getNorthWest())
var bottomRight = map.latLngToLayerPoint(bounds.getSouthEast())
svg.style("width", map.getSize().x + "px")
.style("height", map.getSize().y + "px")
.style("left", topLeft.x + "px")
.style("top", topLeft.y + "px");
g.attr("transform", "translate(" + -topLeft.x + "," + -topLeft.y + ")");
// We reproject our data with the updated projection from leaflet
g.selectAll("circle.dot")
.attr({
cx: function(d) { return project(d).x},
cy: function(d) { return project(d).y},
})
}
// re-render our visualization whenever the view changes
map.on("viewreset", function() {
render()
})
map.on("move", function() {
render()
})
// render our initial visualization
render()
})
</script>
</body>
https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js
https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.js