Proportional symbol map based on secondary data. This map shows proportional symbols based on the city populations minimum and maximum values.
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December 20, 2015 07:19
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D3: Proportional Symbols
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| <!DOCTYPE html> | |
| <meta http-equiv="content-type" content="text/html; charset=utf-8"> | |
| <style> | |
| .states { | |
| fill: #e5e5e5; | |
| stroke: #fff; | |
| stroke-width:1px; | |
| } | |
| .cities { | |
| fill:red; | |
| fill-opacity:0.5; | |
| stroke:#fff; | |
| stroke-width:2px; | |
| } | |
| </style> | |
| <body> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="http://d3js.org/topojson.v1.min.js"></script> | |
| <script src="http://d3js.org/queue.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500; | |
| var svg = d3.select('body').append('svg') | |
| .attr('width', width) | |
| .attr('height', height); | |
| var projection = d3.geo.albersUsa() | |
| .scale(1000) | |
| .translate([width / 2, height / 2]); | |
| var path = d3.geo.path() | |
| .projection(projection); | |
| queue() | |
| .defer(d3.json, '/svmatthews/raw/6090056/states.json') | |
| .defer(d3.json, '/svmatthews/raw/6090056/cities.json') | |
| .await(makeMyMap); | |
| function makeMyMap(error, states, cities) { | |
| var length = cities.features.length; | |
| var pops = []; | |
| for (var mug=0; mug<length; mug++) { | |
| var pop = cities.features[mug].properties.POPULATION; | |
| pops.push(Number(pop)); | |
| } | |
| var min = Math.min.apply(Math, pops); | |
| var max = Math.max.apply(Math, pops); | |
| var radius = d3.scale.sqrt() | |
| .domain([min, max]) | |
| .range([10, 30]); | |
| svg.append('path') | |
| .datum(topojson.feature(states, states.objects.usStates)) | |
| .attr('d', path) | |
| .attr('class', 'states'); | |
| svg.selectAll('.cities') | |
| .data(cities.features) | |
| .enter().append('path') | |
| .attr('class', 'cities') | |
| .attr('d', path.pointRadius(function(d) { return radius(d.properties.POPULATION); })); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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