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d3 mapping code example from https://github.com/larsvers/Learning-D3.js-4-Mapping
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| <!doctype html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Mexico</title> | |
| <style> | |
| .boundary { | |
| fill: none; | |
| stroke: #888; | |
| stroke-linejoin: round; | |
| } | |
| svg { | |
| border-style: solid; | |
| border-width: 1px; | |
| border-color: #ccc; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <div id="map"></div> | |
| <script src="http://d3js.org/d3.v5.min.js" charset="utf-8"></script> | |
| <script src="https://unpkg.com/topojson@3.0.2/dist/topojson.js"></script> | |
| <script> | |
| const jsonUrl = "https://raw.githubusercontent.com/larsvers/Learning-D3.js-4-Mapping/master/chapter-4/geo-data.json" | |
| const height = 600, width = 900 | |
| const projection = d3.geoMercator(); | |
| let mexico = null | |
| const geoID = function(d) { | |
| return `c + ${d.properties.ID_1}`; | |
| }; | |
| const path = d3.geoPath().projection(projection); | |
| const svg = d3.select("#map") | |
| .append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| d3.json(jsonUrl).then(function(data) { | |
| const states = topojson.feature(data, data.objects.MEX_adm1); | |
| let b, s, t; //border, scale, translate | |
| //>___<??, “set an initial scale and translation to 1 and [0,0]” | |
| projection.scale(1).translate([0, 0]); | |
| b = path.bounds(states); | |
| s = .9 / 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); | |
| const map = svg.append('g').attr('class', 'boundary'); | |
| mexico = map.selectAll('path').data(states.features); | |
| mexico.enter() | |
| .append('path') | |
| .attr('d', path) | |
| .attr('id', geoID) | |
| mexico.exit().remove(); | |
| }); | |
| </script> | |
| </body> |
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