In response to a Stack Overflow question regarding centering a map given a GeoJSON object.
Last active
September 30, 2019 23:16
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Project to Bounding Box
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| license: gpl-3.0 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .feature { | |
| fill: #ccc; | |
| } | |
| .mesh { | |
| fill: none; | |
| stroke: #fff; | |
| stroke-width: .5px; | |
| stroke-linejoin: round; | |
| } | |
| .outline { | |
| fill: #ddd; | |
| stroke: #000; | |
| stroke-width: 1.5px; | |
| } | |
| </style> | |
| <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 projection = d3.geo.albers(); | |
| var path = d3.geo.path() | |
| .projection(projection); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| d3.json("/mbostock/raw/4090846/us.json", function(error, us) { | |
| if (error) throw error; | |
| var states = topojson.feature(us, us.objects.states), | |
| state = states.features.filter(function(d) { return d.id === 34; })[0]; | |
| projection | |
| .scale(1) | |
| .translate([0, 0]); | |
| var b = path.bounds(state), | |
| s = .95 / Math.max((b[1][0] - b[0][0]) / width, (b[1][1] - b[0][1]) / height), | |
| t = [(width - s * (b[1][0] + b[0][0])) / 2, (height - s * (b[1][1] + b[0][1])) / 2]; | |
| projection | |
| .scale(s) | |
| .translate(t); | |
| svg.append("path") | |
| .datum(states) | |
| .attr("class", "feature") | |
| .attr("d", path); | |
| svg.append("path") | |
| .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; })) | |
| .attr("class", "mesh") | |
| .attr("d", path); | |
| svg.append("path") | |
| .datum(state) | |
| .attr("class", "outline") | |
| .attr("d", path); | |
| }); | |
| </script> |
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