A demo of the d3.geo.tile plugin, which determines which 256x256 tiles are visible in the viewport based on a scale and translate. This demo combines the tile plugin with d3.behavior.zoom for panning and zooming, resulting in a a simple slippy map. Based partly on an example by Tom MacWright.
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| body { | |
| margin: 0; | |
| } | |
| .map { | |
| position: relative; | |
| overflow: hidden; | |
| } | |
| .layer { | |
| position: absolute; | |
| } | |
| .tile { | |
| pointer-events: none; | |
| position: absolute; | |
| width: 256px; | |
| height: 256px; | |
| } | |
| .info { | |
| position: absolute; | |
| bottom: 10px; | |
| left: 10px; | |
| } | |
| </style> | |
| <body> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="http://d3js.org/d3.geo.tile.v0.min.js"></script> | |
| <script> | |
| var width = Math.max(960, window.innerWidth), | |
| height = Math.max(500, window.innerHeight), | |
| prefix = prefixMatch(["webkit", "ms", "Moz", "O"]); | |
| var tile = d3.geo.tile() | |
| .size([width, height]); | |
| var projection = d3.geo.mercator(); | |
| var zoom = d3.behavior.zoom() | |
| .scale(1 << 12) | |
| .scaleExtent([1 << 9, 1 << 23]) | |
| .translate([width / 2, height / 2]) | |
| .on("zoom", zoomed); | |
| var map = d3.select("body").append("div") | |
| .attr("class", "map") | |
| .style("width", width + "px") | |
| .style("height", height + "px") | |
| .call(zoom) | |
| .on("mousemove", mousemoved); | |
| var layer = map.append("div") | |
| .attr("class", "layer"); | |
| var info = map.append("div") | |
| .attr("class", "info"); | |
| zoomed(); | |
| function zoomed() { | |
| var tiles = tile | |
| .scale(zoom.scale()) | |
| .translate(zoom.translate()) | |
| (); | |
| projection | |
| .scale(zoom.scale() / 2 / Math.PI) | |
| .translate(zoom.translate()); | |
| var image = layer | |
| .style(prefix + "transform", matrix3d(tiles.scale, tiles.translate)) | |
| .selectAll(".tile") | |
| .data(tiles, function(d) { return d; }); | |
| image.exit() | |
| .remove(); | |
| image.enter().append("img") | |
| .attr("class", "tile") | |
| .attr("src", function(d) { return "http://" + ["a", "b", "c", "d"][Math.random() * 4 | 0] + ".tiles.mapbox.com/v3/examples.map-vyofok3q/" + d[2] + "/" + d[0] + "/" + d[1] + ".png"; }) | |
| .style("left", function(d) { return (d[0] << 8) + "px"; }) | |
| .style("top", function(d) { return (d[1] << 8) + "px"; }); | |
| } | |
| function mousemoved() { | |
| info.text(formatLocation(projection.invert(d3.mouse(this)), zoom.scale())); | |
| } | |
| function matrix3d(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 prefixMatch(p) { | |
| var i = -1, n = p.length, s = document.body.style; | |
| while (++i < n) if (p[i] + "Transform" in s) return "-" + p[i].toLowerCase() + "-"; | |
| return ""; | |
| } | |
| 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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