Created
November 20, 2017 15:59
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A simple choropleth map
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| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>D3: Loading GeoJSON data and generating SVG paths</title> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <style type="text/css"> | |
| /* No style rules here yet */ | |
| body,html{ | |
| margin: 0; | |
| padding: 0; | |
| font-family: "Arial", sans-serif; | |
| font-size: 11px; | |
| text-align: center; | |
| } | |
| /* | |
| #chart{ | |
| background-color: #F5F2EB; | |
| border: 1px solid #CCC; | |
| } */ | |
| </style> | |
| </head> | |
| <body> | |
| <script type="text/javascript"> | |
| //Width and height | |
| var w = 500; | |
| var h = 300; | |
| var margin = { | |
| top: 60, | |
| bottom: 40, | |
| left: 70, | |
| right: 40 | |
| }; | |
| var width = w - margin.left - margin.right; | |
| var height = h - margin.top - margin.bottom; | |
| // define map projection | |
| var projection = d3.geoAlbersUsa() | |
| .translate([w/2, h/2]) | |
| .scale([500]); | |
| //Define default path generator | |
| var path = d3.geoPath() | |
| .projection(projection); | |
| var svg = d3.select("body") | |
| .append("svg") | |
| .attr("id", "chart") | |
| .attr("width", w) | |
| .attr("height", h) | |
| .append("g") | |
| .attr("tranform", "translate(0" + margin.left + "," + margin.top + ")"); | |
| var color = d3.scaleQuantile() | |
| .range(["rgb(237, 248, 233)", "rgb(186, 228, 179)", "rgb(116,196,118)", "rgb(49,163,84)", "rgb(0,109,44)"]); | |
| d3.csv("us-cities-agriculture.csv", function(data){ | |
| color.domain([ d3.min(data, function(d){ return d.value; }), | |
| d3.max(data, function(d){ return d.value; }) | |
| ]); | |
| d3.json("us-states.json", function(json){ | |
| //Merge the agriculture and GeoJSON data | |
| //Loop through once for each agriculture data value | |
| for(var i = 0; i < data.length; i++){ | |
| // grab state name | |
| var dataState = data[i].state; | |
| //grab data value, and convert from string to float | |
| var dataValue = parseFloat(data[i].value); | |
| //find the corresponding state inside the GeoJSON | |
| for(var n = 0; n < json.features.length; n++){ | |
| // properties name gets the states name | |
| var jsonState = json.features[n].properties.name; | |
| // if statment to merge by name of state | |
| if(dataState == jsonState){ | |
| //Copy the data value into the JSON | |
| // basically creating a new value column in JSON data | |
| json.features[n].properties.value = dataValue; | |
| //stop looking through the JSON | |
| break; | |
| } | |
| } | |
| } | |
| svg.selectAll("path") | |
| .data(json.features) | |
| .enter() | |
| .append("path") | |
| .attr("d", path) | |
| .style("fill", function(d){ | |
| //get the data value | |
| var value = d.properties.value; | |
| if(value){ | |
| //If value exists | |
| return color(value); | |
| } else { | |
| // If value is undefined | |
| //we do this because alaska and hawaii are not in dataset we are using but still in projections | |
| return "#ccc" | |
| } | |
| }); | |
| }); | |
| }) | |
| </script> | |
| </body> | |
| </html> |
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| state | value | |
|---|---|---|
| Alabama | 1.1791 | |
| Arkansas | 1.3705 | |
| Arizona | 1.3847 | |
| California | 1.7979 | |
| Colorado | 1.0325 | |
| Connecticut | 1.3209 | |
| Delaware | 1.4345 | |
| Florida | 1.6304 | |
| Georgia | 1.3891 | |
| Iowa | 1.5297 | |
| Idaho | 1.4285 | |
| Illinois | 1.5297 | |
| Indiana | 1.4220 | |
| Kansas | 1.0124 | |
| Kentucky | 0.9403 | |
| Louisiana | 0.9904 | |
| Maine | 1.3877 | |
| Maryland | 1.2457 | |
| Massachusetts | 1.1458 | |
| Michigan | 1.1058 | |
| Minnesota | 1.2359 | |
| Missouri | 1.0212 | |
| Mississippi | 1.1306 | |
| Montana | 0.8145 | |
| North Carolina | 1.3554 | |
| North Dakota | 1.0278 | |
| Nebraska | 1.1619 | |
| New Hampshire | 1.0204 | |
| New Jersey | 1.2831 | |
| New Mexico | 0.8925 | |
| Nevada | 0.9640 | |
| New York | 1.1327 | |
| Ohio | 1.2075 | |
| Oklahoma | 0.7693 | |
| Oregon | 1.3154 | |
| Pennsylvania | 1.0601 | |
| Rhode Island | 1.4192 | |
| South Carolina | 1.1247 | |
| South Dakota | 1.0760 | |
| Tennessee | 0.7648 | |
| Texas | 0.8873 | |
| Utah | 0.9638 | |
| Virginia | 0.9660 | |
| Vermont | 1.0762 | |
| Washington | 1.1457 | |
| Wisconsin | 1.1130 | |
| West Virginia | 0.5777 | |
| Wyoming | 0.5712 |
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