Skip to content

Instantly share code, notes, and snippets.

Last active January 30, 2024 20:46
Show Gist options
  • Star 24 You must be signed in to star a gist
  • Fork 33 You must be signed in to fork a gist
  • Save michellechandra/0b2ce4923dc9b5809922 to your computer and use it in GitHub Desktop.
Save michellechandra/0b2ce4923dc9b5809922 to your computer and use it in GitHub Desktop.
Basic US State Map - D3
years place lat lon
2 New York City 40.71455 -74.007124
6 San Francisco 37.7771187 -122.4196396
8 Santa Cruz 36.9740181 -122.0309525
3 Santa Barbara 34.4193802 -119.6990509
10 Tucson 32.22155 -110.9697571
1 Washington DC 38.8903694 -77.0319595
<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8">
<script src=""></script>
<style type="text/css">
/* On mouse hover, lighten state color */
path:hover {
fill-opacity: .7;
/* Style for Custom Tooltip */
div.tooltip {
position: absolute;
text-align: center;
width: 60px;
height: 28px;
padding: 2px;
font: 12px sans-serif;
background: white;
border: 0px;
border-radius: 8px;
pointer-events: none;
/* Legend Font Style */
body {
font: 11px sans-serif;
/* Legend Position Style */
.legend {
<script type="text/javascript">
/* This visualization was made possible by modifying code provided by:
Scott Murray, Choropleth example from "Interactive Data Visualization for the Web"
Malcolm Maclean, tooltips example tutorial
Mike Bostock, Pie Chart Legend */
//Width and height of map
var width = 960;
var height = 500;
// D3 Projection
var projection = d3.geo.albersUsa()
.translate([width/2, height/2]) // translate to center of screen
.scale([1000]); // scale things down so see entire US
// Define path generator
var path = d3.geo.path() // path generator that will convert GeoJSON to SVG paths
.projection(projection); // tell path generator to use albersUsa projection
// Define linear scale for output
var color = d3.scale.linear()
var legendText = ["Cities Lived", "States Lived", "States Visited", "Nada"];
//Create SVG element and append map to the SVG
var svg ="body")
.attr("width", width)
.attr("height", height);
// Append Div for tooltip to SVG
var div ="body")
.attr("class", "tooltip")
.style("opacity", 0);
// Load in my states data!
d3.csv("stateslived.csv", function(data) {
color.domain([0,1,2,3]); // setting the range of the input data
// Load GeoJSON data and merge with states data
d3.json("us-states.json", function(json) {
// Loop through each state data value in the .csv file
for (var i = 0; i < data.length; i++) {
// Grab State Name
var dataState = data[i].state;
// Grab data value
var dataValue = data[i].visited;
// Find the corresponding state inside the GeoJSON
for (var j = 0; j < json.features.length; j++) {
var jsonState = json.features[j];
if (dataState == jsonState) {
// Copy the data value into the JSON
json.features[j].properties.visited = dataValue;
// Stop looking through the JSON
// Bind the data to the SVG and create one path per GeoJSON feature
.attr("d", path)
.style("stroke", "#fff")
.style("stroke-width", "1")
.style("fill", function(d) {
// Get data value
var value =;
if (value) {
//If value exists…
return color(value);
} else {
//If value is undefined…
return "rgb(213,222,217)";
// Map the cities I have lived in!
d3.csv("cities-lived.csv", function(data) {
.attr("cx", function(d) {
return projection([d.lon,])[0];
.attr("cy", function(d) {
return projection([d.lon,])[1];
.attr("r", function(d) {
return Math.sqrt(d.years) * 4;
.style("fill", "rgb(217,91,67)")
.style("opacity", 0.85)
// Modification of custom tooltip code provided by Malcolm Maclean, "D3 Tips and Tricks"
.on("mouseover", function(d) {
.style("opacity", .9);
.style("left", (d3.event.pageX) + "px")
.style("top", (d3.event.pageY - 28) + "px");
// fade out tooltip on mouse out
.on("mouseout", function(d) {
.style("opacity", 0);
// Modified Legend Code from Mike Bostock:
var legend ="body").append("svg")
.attr("class", "legend")
.attr("width", 140)
.attr("height", 200)
.attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });
.attr("width", 18)
.attr("height", 18)
.style("fill", color);
.attr("x", 24)
.attr("y", 9)
.attr("dy", ".35em")
.text(function(d) { return d; });
state visited
Alabama 0
Alaska 0
Arkansas 0
Arizona 2
California 2
Colorado 1
Connecticut 1
Delaware 0
Florida 0
Georgia 0
Hawaii 0
Iowa 0
Idaho 1
Illinois 1
Indiana 0
Kansas 0
Kentucky 0
Louisiana 0
Maine 1
Maryland 1
Massachusetts 1
Michigan 0
Minnesota 1
Missouri 0
Mississippi 0
Montana 1
North Carolina 0
North Dakota 0
Nebraska 0
New Hampshire 1
New Jersey 0
New Mexico 1
Nevada 1
New York 2
Ohio 1
Oklahoma 0
Oregon 1
Pennsylvania 1
Rhode Island 1
South Carolina 0
South Dakota 0
Tennessee 0
Texas 0
Utah 1
Virginia 0
Vermont 0
Washington 1
Wisconsin 0
West Virginia 0
Wyoming 1
Display the source blob
Display the rendered blob
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Copy link

@michellechandra Thank you for writing such informative code! I found this originally at and it has been a big help in getting me acquainted with D3.

I was wondering if you'd be willing to let me license your code, I am working on some projects for my job and would love to use your methods. Let me know if you would like more details!

Copy link

@michellechandra Thank you as well for your informative code! I, too, am wondering if you'd be willing to let me license your code.

Copy link

georgesb commented May 2, 2020

@michellechandra Thank you for this beautiful D3 example! Would it be okay to modify and re-use as an example for high school students? I mostly work with p5.js, but this would be a lovely intro into D3.
ps Just saw your website. I'm a huge Susan Sontag fan. We both went to North Hollywood High. Huge fan of Dan Shiffman of NYU as well.

Copy link

@georgesb - sure, no problem! very cool you went to high school with Susan Sontag!

Copy link

georgesb commented May 2, 2020

Thank you, Michelle! I’ll enjoy learning some D3 with your project! I’m a bit younger than Susan Sontag. 20 years to be exact. She would be 87 now if she were alive. So I never actually met her, but I got into reading her when I was quite young and it was exciting to learn later that she and I had attended the same high school. I'm a semi-retired LAUSD educator and I like to bring in literature and the arts in my CS classes. My website: Thanks again!

Copy link

This is awesome! I was doing a POC on US maps charts and came across your code. I am using ReactJS in AWS-Amplify and some d3 functions are either renamed/moved or not applicable. Managed to get it working, thanks for this.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment