Static tiled raster version of Mike Bostock’s satellite projection example
Minimal Mercator tiles from a [MapBox terrain example](http://a.tiles.mapbox.com/v3/examples.map-4l7djmvo/page.html) are [automatic computed](http://www.jasondavies.com/maps/tile/) and reprojected on-the-fly.
Unfortunately, distortion is too great to support zooming at the moment.
| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <title>Satellite Raster</title> | |
| <style> | |
| @import url(../../maps.css); | |
| #map { | |
| position: relative; | |
| margin: 0 auto; | |
| overflow: hidden; | |
| clip-path: url(#clip); | |
| } | |
| canvas { | |
| cursor: auto; | |
| } | |
| .layer0 { | |
| -webkit-transform: scale(.5); | |
| -webkit-transform-origin: 0 0 0; | |
| } | |
| .layer { | |
| -webkit-transform-origin: 0 0 0; | |
| } | |
| .tile { | |
| position: absolute; | |
| } | |
| </style> | |
| <div id="map"></div> | |
| <script src="http://www.jasondavies.com/d3.min.js"></script> | |
| <script src="http://www.jasondavies.com/maps/d3.geo.projection.min.js"></script> | |
| <script src="http://www.jasondavies.com/maps/topojson.min.js"></script> | |
| <script src="http://www.jasondavies.com/maps/d3.quadtiles.js"></script> | |
| <script> | |
| var ratio = 2, | |
| radians = Math.PI / 180, | |
| width = 960 * ratio, | |
| height = 960 * ratio, | |
| p = .5; | |
| var projection = d3.geo.polyhedron.waterman() | |
| .rotate([20, 0]) | |
| .scale(118) | |
| .translate([width / 2, height / 2]) | |
| .precision(.1); | |
| var path = d3.geo.path().projection(projection); | |
| var layer = d3.select("#map") | |
| .style("width", width / ratio + "px") | |
| .style("height", height / ratio + "px") | |
| .append("div").attr("class", "layer0") | |
| .append("div").attr("class", "layer") | |
| var imgCanvas = document.createElement("canvas"), | |
| imgContext = imgCanvas.getContext("2d"); | |
| function onload(d, canvas, pot) { | |
| var t = projection.translate(), | |
| s = projection.scale(), | |
| c = projection.clipExtent(), | |
| cr = Math.cos(projection.clipAngle() * radians), | |
| image = d.image, | |
| dx = image.width, | |
| dy = image.height, | |
| k = d.key, | |
| width = 1 << k[2]; | |
| projection.translate([0, 0]).scale(1 << pot).clipExtent(null); | |
| imgCanvas.width = dx, imgCanvas.height = dy; | |
| imgContext.drawImage(image, 0, 0, dx, dy); | |
| var bounds = path.bounds(d), | |
| x0 = d.x0 = bounds[0][0] | 0, | |
| y0 = d.y0 = bounds[0][1] | 0, | |
| x1 = bounds[1][0] + 1 | 0, | |
| y1 = bounds[1][1] + 1 | 0; | |
| var λ0 = k[0] / width * 360 - 180, | |
| λ1 = (k[0] + 1) / width * 360 - 180, | |
| φ1 = mercatorφ(k[1] / width * 360 - 180), | |
| φ0 = mercatorφ((k[1] + 1) / width * 360 - 180); | |
| var width = canvas.width = x1 - x0, | |
| height = canvas.height = y1 - y0, | |
| context = canvas.getContext("2d"); | |
| if (width > 0 && height > 0) { | |
| var sourceData = imgContext.getImageData(0, 0, dx, dy).data, | |
| target = context.createImageData(width, height), | |
| targetData = target.data; | |
| for (var y = y0, i = -1; y < y1; ++y) { | |
| for (var x = x0; x < x1; ++x) { | |
| var p = projection.invert([x, y]), λ = p[0], φ = p[1]; | |
| if (isNaN(λ) || isNaN(φ) || λ > λ1 || λ < λ0 || φ > φ1 || φ < φ0) { i += 4; continue; } | |
| var q = (((λ - λ0) / (λ1 - λ0) * dx | 0) + ((φ1 - φ) / (φ1 - φ0) * dy | 0) * dx) * 4; | |
| //var q = ((90 - φ) / 180 * dy | 0) * dx + ((180 + λ) / 360 * dx | 0) << 2; | |
| targetData[++i] = sourceData[q]; | |
| targetData[++i] = sourceData[++q]; | |
| targetData[++i] = sourceData[++q]; | |
| targetData[++i] = 255; | |
| } | |
| } | |
| context.putImageData(target, 0, 0); | |
| } | |
| d3.selectAll([canvas]) | |
| .style("left", x0 + "px") | |
| .style("top", y0 + "px"); | |
| projection.translate(t).scale(s).clipExtent(c); | |
| } | |
| redraw(); | |
| function redraw() { | |
| // TODO improve zoom level computation | |
| var pot = Math.log(projection.scale()) / Math.LN2 | 0, | |
| ds = projection.scale() / (1 << pot), | |
| t = projection.translate(), | |
| z = pot - 6; | |
| layer.style("-webkit-transform", "translate(" + t.map(pixel) + ")scale(" + ds + ")"); | |
| var tile = layer.selectAll(".tile") | |
| .data(d3.quadTiles(projection, z), key); | |
| tile.enter().append("canvas") | |
| .attr("class", "tile") | |
| .each(function(d) { | |
| var canvas = this; | |
| var image = d.image = new Image; | |
| image.crossOrigin = true; | |
| image.onload = function() { setTimeout(function() { onload(d, canvas, pot); }, 1); }; | |
| var k = d.key; | |
| image.src = "http://" + ["a", "b", "c"][(k[0] * 31 + k[1]) % 3] + ".tile.stamen.com/watercolor/" + k[2] + "/" + k[0] + "/" + k[1] + ".jpg"; | |
| }); | |
| tile.exit().remove(); | |
| } | |
| function key(d) { return d.key.join(", "); } | |
| function mercatorφ(y) { | |
| return Math.atan(Math.exp(-y * Math.PI / 180)) * 360 / Math.PI - 90; | |
| } | |
| function pixel(d) { return (d | 0) + "px"; } | |
| </script> |