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@mbostock /.block
Last active Jan 30, 2017

Vector Tiles
license: gpl-3.0
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
margin: 0;
}
.map {
position: relative;
overflow: hidden;
}
.layer {
position: absolute;
will-change: transform;
}
.tile {
position: absolute;
width: 256px;
height: 256px;
}
.tile path {
fill: none;
stroke: #000;
stroke-linejoin: round;
stroke-linecap: round;
}
.tile .major_road {
stroke: #776;
}
.tile .minor_road {
stroke: #ccb;
}
.tile .highway {
stroke: #f39;
stroke-width: 1.5px;
}
.tile .rail {
stroke: #7de;
}
.info {
position: absolute;
bottom: 10px;
left: 10px;
}
</style>
<body>
<script src="//d3js.org/d3.v4.min.js"></script>
<script src="//d3js.org/d3-tile.v0.0.min.js"></script>
<script>
var pi = Math.PI,
tau = 2 * pi;
var width = Math.max(960, window.innerWidth),
height = Math.max(500, window.innerHeight);
// Initialize the projection to fit the world in a 1×1 square centered at the origin.
var projection = d3.geoMercator()
.scale(1 / tau)
.translate([0, 0]);
var path = d3.geoPath()
.projection(projection);
var tile = d3.tile()
.size([width, height]);
var zoom = d3.zoom()
.scaleExtent([1 << 20, 1 << 23])
.on("zoom", zoomed);
var map = d3.select("body").append("div")
.attr("class", "map")
.style("width", width + "px")
.style("height", height + "px")
.on("mousemove", mousemoved);
var layer = map.append("div")
.attr("class", "layer");
var info = map.append("div")
.attr("class", "info");
// Compute the projected initial center.
var center = projection([-74.0064, 40.7142]);
// Apply a zoom transform equivalent to projection.{scale,translate,center}.
map .call(zoom)
.call(zoom.transform, d3.zoomIdentity
.translate(width / 2, height / 2)
.scale(1 << 20)
.translate(-center[0], -center[1]));
function zoomed() {
var transform = d3.event.transform;
var tiles = tile
.scale(transform.k)
.translate([transform.x, transform.y])
();
projection
.scale(transform.k / tau)
.translate([transform.x, transform.y]);
var image = layer
.style("transform", stringify(tiles.scale, tiles.translate))
.selectAll(".tile")
.data(tiles, function(d) { return d; });
image.exit()
.each(function(d) { this._xhr.abort(); })
.remove();
image.enter().append("svg")
.attr("class", "tile")
.style("left", function(d) { return d[0] * 256 + "px"; })
.style("top", function(d) { return d[1] * 256 + "px"; })
.each(function(d) { this._xhr = render(d, this); });
}
function render(d, node) {
return d3.json("https://vector.mapzen.com/osm/roads/" + d[2] + "/" + d[0] + "/" + d[1] + ".json?api_key=vector-tiles-LM25tq4", function(error, json) {
if (error) throw error;
var k = Math.pow(2, d[2]) * 256; // size of the world in pixels
d3.select(node).selectAll("path")
.data(json.features.sort(function(a, b) { return a.properties.sort_key - b.properties.sort_key; }))
.enter().append("path")
.attr("class", function(d) { return d.properties.kind; })
.attr("d", d3.geoPath()
.projection(d3.geoMercator()
.scale(k / tau)
.translate([k / 2 - d[0] * 256, k / 2 - d[1] * 256])
.precision(0)));
});
}
function stringify(scale, translate) {
var k = scale / 256, r = scale % 1 ? Number : Math.round;
return "matrix3d(" + [k, 0, 0, 0, 0, k, 0, 0, 0, 0, k, 0, r(translate[0] * scale), r(translate[1] * scale), 0, 1 ] + ")";
}
function mousemoved() {
info.text(formatLocation(projection.invert(d3.mouse(this)), d3.zoomTransform(this).k));
}
function formatLocation(p, k) {
var format = d3.format("." + Math.floor(Math.log(k) / 2 - 2) + "f");
return (p[1] < 0 ? format(-p[1]) + "°S" : format(p[1]) + "°N") + " "
+ (p[0] < 0 ? format(-p[0]) + "°W" : format(p[0]) + "°E");
}
</script>
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