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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