The Land of Single-Family Homes

Americans really like detached single-family homes. In European cities apartment living results in more densely populated urban centers than in most U.S. cities. In most U.S. cities land is often zoned to prevent the type of dense residential development that is common in many European cities.The result is that many cities in America are now witnessing an affordable housing crisis.

The New York Times has mapped out the areas of U.S. cities which are zoned for detached single-family housing and the amount of land zoned for other types of housing (for example apartment blocks). In Cities Start to Question an American Ideal: A House With a Yard on Every Lot the NYT claims that many cities and states are now changing their planning regulations to promote the development of non single-family housing.

The multiple small maps in the NYT article use data from UrbanFootprint to show the areas in a number of different cities which are zoned for detached single-family homes. Later in the article the NYT shows these individual cities with larger maps. These larger maps include a percentage total of how much of the city is zoned for detached single-family housing. For example 70% of residential land in Minneapolis is zoned for detached single-family homes.

California is one state which is trying to encourage the development of other more densely packed types of housing. In an attempt to address California's housing supply crisis Senator Scott Wiener has introduced a bill which is designed to encourage the building of apartment buildings in areas with good transit, at the expense of single family homes. If passed the bill will prevent cities and towns from stopping the construction of apartment buildings in certain areas.


Of course not all single-family home owners are happy at the prospect of new tall apartment buildings being constructed in their neighborhoods. The creators of the Stop SB50 Wrecking Homes are definitely opposed to State Senator Scott Wiener's SB-50 bill. The site claims that "SB 50 is an unprecedented law that will destroy thousands of homes & apartments to build luxury housing up to 8 stories high".

This opposition to the bill shouldn't make much difference to their maps as long as they use accurate data. On the Stop SB50 Wrecking Family Homes interactive map three colors are used to show areas where 'Buildings up to 85' feet could be allowed, where 'Buildings up to 75' feet could be built and where 'Buildings up to 75 feet (in jobs rich/good school areas)' will be permitted.


In Peeling the SB 50 Onion UrbanFootprint has also mapped out how SB50 could impact areas in California's largest metropolitan areas. The UrbanFootprint map uses different colors to show zones which are near transit stops, in high quality transit corridors and which are seen as jobs-rich.

In the NYT article San Jose and Los Angeles in California have both been mapped to show how much of these cities' residential zones are currently zoned for detached single-family homes. In San Jose 94% of residential land is zoned for detached single-family homes. In Los Angeles 75% of residential land is zoned only for detached single-family homes. The result is that the West Coast has a huge affordable housing shortage.

The Global Human Footprint

The European Space Agency has released a new interactive map which shows how much of the world has been built upon by the human race. The world's population is now over 7.5 billion. All those people have got to live somewhere - and most of them live in urbanized areas.

ESA's World Settlement Footprint interactive map visualizes human settlements around the world. The map was created from an analysis of satellite imagery collected during 2014-15. The map reveals how much of the world has been urbanized, where urbanization is most dense and which parts of the Earth are still untouched by human settlement.

The Global Rural Urban Mapping Project estimates that around 3% of the world has now been urbanized. Of course the percentage of land which is urbanized varies from country to country. For example 5.9% of the UK is built upon. Even more of the Netherlands has been developed. It is estimated that 14% of the densely populated Netherlands is built upon. On the other side of the Atlantic, in the less densely populated United States, only 3.6% of the land has been developed.

Later this year the World Settlement Footprint map will include an option to view how urban settlements have developed and grown since 1985. The map will use six million satellite images, from 1985 to 2015, to visualize the growth of human settlements on a year-by-year basis around the globe.


Of course if we want to leave most of the world free from human development we will have to learn to live in more densely populated towns and cities. The Pudding has an impressive interactive map which visualizes the world's population in 3D. The Pudding's Human Terrain interactive map shows population density across the globe using 3D population pyramids. The taller a pyramid block on The Pudding map then the more people live there.

The Pudding has also used its own map to explore in more detail the pattern of population density around the world. In Population Mountains The Pudding examines how unevenly the world is populated and how population density can take different forms in different parts of the world.

The Most Famous Czechs Map

The Holy Roman Emperor, King Charles IV, is the most famous person to have been born in the Czech Republic, according to Wikipedia. More people visit the Wikipedia page of Charles IV (Karel IV) than the Wikipedia entry of any other Czech person.

You can find out who is the most famous person from every Czech town on a new interactive map by iROZHLAS. The Most Popular Natives of Czech Towns map reveals the native person with the most Wikipedia visits for 1,749 towns and cities. You can learn more about each of the labeled people by simply hovering over their name on the map. This will reveal a very brief biography and a link to their Wikipedia entry.

iROZHLAS's map was of course inspired by The Pudding's very popular A People Map of the USA, showing the most famous person from each U.S. town and The Pudding's similar map for the UK, A People Map of the UK.

The Legacy of Redlining

Under President Franklin D. Roosevelt's New Deal black homeowners were discriminated against through the creation of redlining maps. These maps identified areas with significant black populations and labeled them as too high risk for mortgage support. Black homeowners living in these areas were therefore very unlikely to be successful when trying to refinance home mortgages from the government sponsored Home Owners' Loan Corporation.

Wenfei Xu has released a new interactive mapping tool which allows you to compare the historical redlining maps side-by-side with modern day census data. The Redlining Map tool allows you to explore for yourself if the HOLC redlining maps have had a lasting impact on segregation in your city. Using the modern census data you can view the neighborhoods with a high percentage of black, white or Hispanic people and see if these areas correlate with areas which were deemed at risk or safe for lending purposes in the 1930's.

On the original Home Owners' Loan Corporation redlining maps the areas marked in blue were the neighborhoods deemed desirable for lending purposes. The yellow areas show the neighborhoods which were deemed 'declining' areas. The red areas were the neighborhoods considered the most risky for mortgage support. You can use Wenfei Xu's Redlining Map to see if the areas marked red in the 1930's redlining maps are areas which still have a large black population. You can also see if the blue or 'First Grade' areas are areas which still have a significantly large white population.


The HOLC map from the National Community Reinvestment Coalition also allows you to explore the lasting legacy of the HOLC's redlining maps. This interactive map allows you to compare modern data about income status and the minority population with the HOLC's historical redlining security ratings.

Using the HOLC map you can see if neighborhoods in your city with 'good' HOLC redlining ratings have remained largely white and wealthy or whether your city has become a beacon of social and racial equality. You can also use the National Community Reinvestment Coalition map to see where gentrification has occurred in a city. These are the neighborhoods which received the lowest HOLC redlining ratings but now don't have the stripes from the 'Low to Moderate Income' layer.

Get Your Global Heating Stripes

Last year Ed Hawkins, a climate scientist at the National Centre for Atmospheric Science at the University of Reading, released a powerful data visualization to illustrate how temperatures have risen around the globe over the last century. His warming stripes visualization shows the average yearly temperature for every year over 100+ years.

You can now get your own warming stripes for different regions and countries around the world (and for individual U.S. states). Select a region and then a country from the drop-down menu on #ShowYourStripes and you can view and download an image showing how temperatures have risen over the last 100+ years at your selected location.

Global warming stripes are a very powerful way to visualize a complex issue with one simple and easy to understand image. The general progress from blue to redder stripes is both visually striking and very hard to dispute. The temperature data used for creating the stripes come from the Berkeley Earth temperature dataset and from a number of national meteorological agencies.

America's Most Bike Friendly Cities

Provincetown in Massachusetts is the most bike friendly city in the USA. Alma, Michigan is the second best city for cyclists. Davis, California comes third. You can find out how bike friendly your city is on PeopleforBikes. PeopleforBikes BNA has ranked cities across the United States and Canada based on how easy they are to travel around by bike.

The PeopleforBikes Bike Network Analysis (BNA) ranks towns and cities based on traffic stress, destination access and score aggregation. Traffic stress is calculated by looking at the type of cycling infrastructure available (e.g. the availability of bike lanes, bake paths etc). Destination access is determined by looking at how easy (unstressful) it is to travel across a city by bike. Score aggregation looks at how friendly every census block is for cyclists across the whole city.

PeopleforBikes BNA has created interactive maps for 571 different U.S. and Canadian cities. Each of these individual maps shows the city's overall BNA score. The map also colors all the city's roads to show whether they are high (red) or low (blue) stress for cyclists. The map sidebar includes information on how easy it is to access different services by bike. It also shows how easy it is to access recreational and transportation facilities by bike.

Which Europeans Believe in God?

The Romanians are the most religious people in Europe. 55% of Romanians say that they are 'highly religious'. Estonia is Europe's least religious country. Only 7% of the Estonian population say that they are 'highly religious'. Despite being the most 'highly religious' people in Europe Romanians aren't Europe's biggest believers in God. That privilege belongs to Armenia, where 79% of the people say they believe in a Supreme Being. In comparison only 64% of Romanians believe in God.

According to the Pew Research Center Europeans are generally less religious than people in the rest of the world. However the religious commitment of Europeans varies greatly from country to country. The Pew Research Center has therefore decided to map out the religiosity of European countries.

The interactive map in How Do European Countries Differ in Religious Commitment? shows the percentage of people in each European country who self-identify as 'highly religious'. The Pew Research Center surveyed Europeans on five different questions about their religious belief and practice. The map only shows the results for Europeans' overall religiosity (the percentage of the population who say they are 'highly religious'). However you can view the results from the other four questions about religion in a series of tables. These tables order European countries, from most religious to least, giving the percentage of people who identified as religious in each of the separate questions.

Mapping UK Marine Traffic

Last year Alasdair Rae mapped out the tracks and routes taken by different types of ships around the UK. In Watching the Ships Go By Alasdair created a series of maps to visualize the paths taken by different marine vessels in UK coastal waters. These maps show the different shipping routes taken by cargo ships, passenger ships, fishing boats, high speed craft, military vessels, tankers and recreational craft.

Esri UK has now released a series of similar maps visualizing 2015 marine traffic to reveal the different tracks created by the different types of marine vessel. What Goes on in UK Waters uses AIS data to visualize and explore the different traffic routes taken by commercial, military, fishing, passenger, and recreational boats in UK waters.

The seas around the UK contain some of the world's busiest shipping lanes. The Strait of Dover is just 20.7 miles wide (From England to France) at its narrowest point. Around 600 ships a day pass through this narrow strait. Esri's map of cargo shipping lanes provides a neat visualization of this heavy traffic through the English Channel. While all this commercial shipping traffic passes through the Channel passenger ferries cross these busy shipping lanes traveling between France and England. You can see these passenger ferry lanes on Esri's map of passenger crossings.

Esri's series of maps includes a map showing marine activity during Cowes week (a huge regatta held each year in the Solent). It also includes a map showing recreational marine traffic in the winter and a map showing recreational marine traffic in the summer (people don't seem to take their boats out much during the Winter months).

Can You Guess the Airport From its Map?

These nine maps show the nine largest airports in the world by passenger numbers. The airports were chosen based on International Airport Reviews Top 20 Airports list.

Can you identify each airport based only on its map? As a very infrequent flyer I would find this challenge impossible myself. I've therefore included the IATA three letter codes for each airport as a clue (I still wouldn't be able to name eight of the airports). Answers are given at the bottom of this post.

While creating these maps I was reminded of the brilliant Trails of Wind interactive map of global airport runway orientations. More runways around the world are built on a north-south orientation than on a east-west axis. You can see this beautifully visualized on the Trails of Wind map. On this interactive map airport runways around the world are colored based on their orientation.

Answers (select text below to reveal)

London Heathrow (LHR), Shanghai Pudong (PVG), Los Angeles (LAX)

Hartsfield-Jackson Atlanta (ATL), Beijing Capital (PEK), Dubai (DXB)

Tokyo Hanenda (HND), O'Hare Chicago (ORD), Hong Kong (HKA)

You might also like to play Name the City from its Road Network and Name the Country From its Rail Network

Internal Migration in the USA

More people moved out of Los Angeles County than left any other county in the USA between 2015 and 2016. However more people also moved into Los Angeles County than moved into any other county in the country. Esri has mapped out the top twenty counties with the highest outbound and inbound migrations between 2015 and 2016. A lot of counties, like Los Angeles County, appear in the top twenty counties for both outbound and inbound migration. One reason for this is that many of the counties with the highest levels of migration are the most populated counties.

Esri has used data from the IRS to map internal migration in the USA. The Internal Revenue Service records when Americans move address every time they file taxes in a new state. Esri has used this data to map the movements between states and between counties between 2015-2016.

Using the IRS data Esri has created two maps for each state, showing inbound and outbound migration. These maps show which other states people are moving to when they leave a state and which states people are moving from into each U.S. state. Esri has also used the IRS data to show the twenty counties in the country with the biggest outbound migration (and which counties people moved to) and the twenty counties with the biggest inbound migration (and which counties they moved from).

You can view Esri's U.S. internal migration maps either on the Where are Americans Moving Story Map or on the Visualizing Population Migration blog post. Both feature the same maps which use Esri's Distributive Flow Lines tool to create the migration flow visualizations.


You can also view state-to-state migration flows in the United States, from 2009-2013, on the US Migration Flow Map. This map shows that Texas was the most popular destination for Californians moving out of the Golden State during these years. The love that Californians have for Texas was   reciprocated, as California was the most popular destination for Texans moving out of state.

This interactive map by Oregon State University allows you to see which states are the most popular destinations for Americans moving house. The US Migration Flow Map uses flow lines to visualize the numbers of people moving between different states in the USA from 2009-2013. The map includes options to see which states have the biggest exchanges of citizens and to view the most popular state destinations for each individual state.


You can see where people move to and from at the city level in the American Migration interactive map. American Migration visualizes where people moved to and from in America from 2011-2015.

If you hover over a city on the map you can see all the other cities where people moved to, according to the Census Bureau's 2011-2015 American Community Survey. The map uses the Metro to Metro Migration Flows from the survey, which asks respondents if they've moved in the last year where they lived one year ago. As well as the flow-lines on the map, which show all the cities people have moved to, a top 5 list shows the most popular destinations for people moving from the selected city.

Creating Flowmaps

If you are want to create your own flowmaps to visualize movement then you might be interested in Sarah Bellum's Canvas Flowmap Layer, a popular ArcGIS JavaScript API library, which allows you to map objects flowing from one location to another.

The Flowmap-Layer is also now available as a custom map layer for the Leaflet JavaScript mapping library. Like the original ArcGIS flowmap layer Leaflet.Canvas-Flowmap-Layer uses Bezier curves to visualize the movement of objects from one location to another on an interactive map.