A demonstration of D3 3.3’s new zoom transitions. For best viewing experience, please play “Doin’ It Right (feat. Panda Bear)” off the latest Daft Punk album while watching this animation.
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June 16, 2023 22:51
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Map Zooming
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| license: gpl-3.0 | |
| redirect: https://observablehq.com/@d3/map-zooming |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="//d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500; | |
| var sf = [-122.417, 37.775], | |
| ny = [-74.0064, 40.7142]; | |
| var scale, | |
| translate, | |
| visibleArea, // minimum area threshold for points inside viewport | |
| invisibleArea; // minimum area threshold for points outside viewport | |
| var simplify = d3.geo.transform({ | |
| point: function(x, y, z) { | |
| if (z < visibleArea) return; | |
| x = x * scale + translate[0]; | |
| y = y * scale + translate[1]; | |
| if (x >= -10 && x <= width + 10 && y >= -10 && y <= height + 10 || z >= invisibleArea) this.stream.point(x, y); | |
| } | |
| }); | |
| var zoom = d3.behavior.zoom() | |
| .size([width, height]) | |
| .on("zoom", zoomed); | |
| // This projection is baked into the TopoJSON file, | |
| // but is used here to compute the desired zoom translate. | |
| var projection = d3.geo.mercator() | |
| .translate([0, 0]) | |
| .scale(4000); | |
| var canvas = d3.select("body").append("canvas") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var context = canvas.node().getContext("2d"); | |
| var path = d3.geo.path() | |
| .projection(simplify) | |
| .context(context); | |
| d3.json("us-states.json", function(error, json) { | |
| if (error) throw error; | |
| canvas | |
| .datum(topojson.mesh(topojson.presimplify(json))) | |
| .call(zoomTo(sf, 4).event) | |
| .transition() | |
| .duration(60 * 1000 / 89 * 2) | |
| .each(jump); | |
| }); | |
| function zoomTo(location, scale) { | |
| var point = projection(location); | |
| return zoom | |
| .translate([width / 2 - point[0] * scale, height / 2 - point[1] * scale]) | |
| .scale(scale); | |
| } | |
| function zoomed(d) { | |
| translate = zoom.translate(); | |
| scale = zoom.scale(); | |
| visibleArea = 1 / scale / scale; | |
| invisibleArea = 200 * visibleArea; | |
| context.clearRect(0, 0, width, height); | |
| context.beginPath(); | |
| path(d); | |
| context.stroke(); | |
| } | |
| function jump() { | |
| var t = d3.select(this); | |
| (function repeat() { | |
| t = t.transition() | |
| .call(zoomTo(ny, 6).event) | |
| .transition() | |
| .call(zoomTo(sf, 4).event) | |
| .each("end", repeat); | |
| })(); | |
| } | |
| </script> |
I finally found where the us-states came from: https://github.com/mbostock/us-atlas
Thanks so much for this. Amen!
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Nailed it! The tempo is bang on :)