Posts for Tag: choropleth

Which State Borders the Most Other States?

Posted In: Maps

Interactive Choropleth of the Number of States That Border Each State

This is a fun little map that shows the number of states that border each state. I’m working on improving the interactivity of maps and this was a good project to try this with. The base map is a choropleth map which color codes each state by the number of states it shares a border with. If you hover over (or touch on mobile) a state, it will highlight the state and show you (and list) the bordering states.

It’s important to note that officially New York and Rhode Island share a water border (between Rhode Island and Long Island, NY) and that Michigan and Minnesota also share a border (in Lake Superior).

Sources and Tools:

Data on state borders was downloaded from And the visualization was created using javascript and the open source leaflet javascript mapping library.

state borders

Tracking US Coronavirus Cases by State

Posted In: Maps

The coronavirus (SARS-CoV-2) is literally affecting the entire globe right now and changing the way we live our lives here in the US and all over the world.

There are quite a number of different coronavirus-related dataviz out there, but as we shelter-in-place I wanted to add a map that looked at a number of different metrics that tell us about the coronavirus pandemic by US states and look at those metrics on a population basis.

There are a number of data sources that I’ve found that publish data about the coronavirus and the resulting disease (Covid-19) in the United States:

This map is based on the data compiled from, partly because it has a good API and also lists testing, cases and deaths. The data I’ve included on the map is:

  • Numbers of coronavirus cases – i.e. tested positive for virus
  • Numbers of coronavirus tests administered
  • Numbers of deaths due to coronavirus

Each of these is also calculated per 100,000 population in the state:

  • Numbers of coronavirus cases per 100k people- i.e. tested positive for virus
  • Numbers of coronavirus tests administered per 100k people
  • Numbers of deaths due to coronavirus per 100k people

These latter metrics are important because numbers of cases or deaths can be obscured by small or large populations but per capita data (or per 100k capita data) can point out interesting outliers.

It is important to note that the data is far from perfect. There is probably significant underreporting of tests, cases and deaths. The data is a collection for the various local and state agencies that are working hard to deal with the medical, social and political ramifications of the pandemic, while also collecting data. We don’t know how many Americans have coronavirus because of lack of testing.

Also important is that the number of positive cases is a function of how much testing is taking place so cases does not necessarily represent the exact prevalence of the virus, though there will probably be good correlation between cases and actual coronavirus infections. Luckily it sounds like tests are becoming more widely available so hopefully those numbers will go up sharply.

For more information about the virus and the disease and data collection, you can find good information on the CDC website.

Sources and Tools:

Coronavirus cases are obtained from And the visualization was created using javascript and the open source leaflet javascript mapping library.

coronavirus by state

Assembling the USA state-by-state with state-level statistics

Posted In: Maps

Watch the United States assemble state by state based on statistics of interest

Based on earlier popularity of the country-by-country animation, this map lets you watch as the world is built-up one state at a time. This can be done along a large range of statistical dimensions:

  • Name (alphabetical)
  • abbreviation
  • Date of entry to the United States
  • State Population (2018)
  • Population per Electoral Vote (2018)
  • Population per House Seat (2018)
  • Land Area (square miles)
  • Population Density (ppl per sq mi) (2018)
  • State’s Highest Point
  • Highest Elevation (ft)
  • Mean Elevation (ft)
  • State’s Lowest Point
  • Lowest Point (ft)
  • Life Expectancy at Birth (yrs)
  • Median Age (yrs)
  • Percent with High School Education
  • Percent with Bachelor’s Degree
  • Residential Electricity Price (cents per kWh) (2018)
  • Gasoline Price ($/gal) Regular unleaded (2019)
  • State Gross Domestic Product GDP ($Million) (2018)
  • GDP per capita ($/capita)
  • Number of Counties (or subdivisions)
  • Average Daily Solar Radiation (kWh/m2)
  • Birth rate (per thousand population)
  • Avg Age of Mother at Birth
  • Annual Precipitation (in/yr)
  • Average Temperature (deg F)
  • These statistics can be sorted from small to large or vice versa to get a view of the US and its constituent states plus DC in a unique and interesting way. It’s a bit hypnotic to watch as the states appear and add to the country one by one.

    You can use this map to display all the states that have higher life expectancy than the Texas:
    select “Life expectancy”, sort from “high to low” and use the scroll bar to move to the Texax and you’ll get a picture like this:
    States with higher life expectancy than Texas

    or this map to display all the states that have higher population density than California:
    select “Population density, sort from “high to low” and use the scroll bar to move to the United States and you’ll get a picture like this:
    States with higher population density than California

    I hope you enjoy exploring the United States through a number of different demographic, economic and physical characteristics through this data viz tool. And if you have ideas for other statistics to add, I will try to do so.

    Data and tools: Data was downloaded from a variety of sources:

    • Population
    • Admission to union
    • Educational attainment
    • Highest points
    • Life expectancy
    • Median Age
    • Land area
    • Mean elevation
    • Electricity price
    • Gasoline price
    • GDP
    • Sunlight North America Land Data Assimilation System (NLDAS) Daily Sunlight (insolation) for years 1979-2011 on CDC WONDER Online Database, released 2013. Accessed at on Jun 14, 2019 1:37:15 PM
    • Births United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2007-2017, on CDC WONDER Online Database, October 2018. Accessed at on Jun 14, 2019 1:53:58 PM
    • Precipitation North America Land Data Assimilation System (NLDAS) Daily Precipitation for years 1979-2011 on CDC WONDER Online Database, released 2013. Accessed at on Jun 26, 2019 3:30:40 PM
    • Temperature–average-temperature–state-rank.htm

    The map was created with the help of the open source leaflet javascript mapping library

    What kinds of vehicles do Americans drive?

    Posted In: Energy

    Americans are known for loving cars and driving quite a bit. Drivers in the United States own more cars and drive more than those in any other country. So what kinds of vehicles do Americans drive? This visualization looks at the types of vehicles (by body type and country of origin) across the 50 States and Washington DC.

    You can view two different attributes about the types of vehicles in use in the United States:

    • Body type of passenger vehicles
    • Manufacturer/Brand region of origin

    The different categories of passenger vehicles include:

    • Cars – includes sedans, hatchbacks, wagons and sports cars
    • Pickup trucks
    • SUVs
    • Vans – includes Minivans and full-size vans

    Classification of the vehicles manufacturer (US, Asia or Europe) is based on the company’s headquarters and not the place of vehicle manufacturing. So a Toyota here is an Asian vehicle even if it was assembled in Mississippi.

    It is pretty interesting to see the regional differences in vehicle types (cars vs trucks and SUVs) and vehicle brand (domestic vs foreign). Michigan, especially, stands out with their very high domestic ownership. It makes sense as Detroit is the home of the big three US auto manufacturers (Ford, GM and Chrysler). And I hear there’s a very strong culture of owning American cars there (and employee, friends and family discounts as well).

    The data is derived from a survey by the US Department of Transportation called the National Household Travel Survey (NHTS) released in 2017. The following is a quote from the NHTS webpage:

    The National Household Travel Survey (NHTS) is the source of the Nation’s information about travel by U.S. residents in all 50 States and Washington, DC. This inventory of travel behavior includes trips made by all modes of travel (i.e., private vehicle, public transportation, pedestrian, and cycling) and for all purposes (e.g., travel to work, school, recreation, and personal/family trips). It provides information to assist transportation planners and policymakers who need comprehensive data on travel and transportation patterns in the United States.

    Data and Tools:
    Data, as stated before, comes from the US Department of Transportation’s National Household Travel Survey (NHTS). That data was processed to identify vehicle characteristics by state and plotted using javascript and the open-source leaflet map library.

    car types by state

    How Much Does Each State Pay In Taxes?

    Posted In: Money

    Given that tax day has just passed, I thought it would be good to check out some data on taxes. The IRS provides a great resource on tax data that I’ve only just gotten into. I think I’ll be able to do more with this in the future. This one looks at how taxes paid varies by state and presents it as a choropleth map (coloring states based on certain categories of tax data).

    You can choose from a number of different categories:

    • Mean Federal Tax Paid
    • Mean Adjusted Gross Income
    • Mean State/Local Tax
    • Mean Combined (Fed/State/Local) Tax
    • Percent Income from Dividends and Capital Gains
    • Percent of Returns with Itemized Deductions
    • Number of Tax Returns
    • Mean Federal Tax Rate
    • Mean State/Local Tax Rate
    • Mean Combined (Fed/State/Local) Rate
    • Total Federal Tax Liability

    I may add more categories in the future, so if you have ideas of tax data you want to see visualized let me know and I’ll see what I can do.

    For other tax-related tools and visualizations see my tax bracket calculator and visualization of marginal tax rates.

    **Click Here to view other financial-related tools and data visualizations from engaging-data**

    Data and Tools:

    Data on tax returns by state is from the IRS website in an excel format. The map was made using the leaflet open source mapping library. Data was compiled in excel and calculations made using javascript.

    How much each state paid in taxes

    Electric Vehicle Sales By State

    Posted In: Energy | Technology

    Where are electric vehicles being sold in the United States?

    Electric vehicles are any vehicle that can be plugged in to recharge a battery that provides power to move the vehicle. Two broad classes are battery electric vehicles (BEVs) which only have batteries as their power source and plug-in hybrid electric vehicles (PHEVs) which have an alternative or parallel power source, typically a gasoline engine. PHEVs are built so that when the battery is depleted, the car can still run on gasoline and operate like a hybrid vehicle similar to a regular Toyota Prius (which is not plugged in at all).

    Electric vehicles (EVs) have been sold in the US since 2011 (a few commercial models were sold previous to that but not in any significant numbers) and some conversions were also available. Since then, the number of EVs sold has increased pretty significantly. I wanted to look at the distribution of where those vehicles were located. What is interesting is that California accounts for around 50% of the electric vehicles sold in the United States. Other states have lower rates of EV adoption (in some cases much, much lower). There are many reasons for this, including beneficial policies, public awareness, a large number of potential early adopters and a mild climate. Even so, the EV heatmap of California done early shows that sales are mostly limited to the Bay Area, and LA areas.

    The map shows data for total electric vehicle sales by state for years 2016, 2017 or 2018 and also the number of EV sales per 1000 licensed drivers (this is all people in the state with a drivers license, not drivers of EVs). If you hover over a state, you can see both data points for that state.

    It will be interesting to see how the next generation of electric vehicles continues to improve, lower in price and become more popular with drivers outside of early adopters.

    Data and Tools:
    Data on electric vehicle sales is from the Auto Alliance website. Licensed driver data was downloaded from the US Department of Transportation’s Bureau of Transportation Statistics website. The map was made using the leaflet open source mapping library. Data was compiled and calculated using javascript.

    Electric vehicle sales by state