California's Rental Calculator

If you want to rent a property in California then you can use a new interactive map from the Los Angeles Times to discover the zip-code areas which have properties within your price range. Just enter your income into the Where can you afford to rent in California? and all zip-code areas in the state will be colored to show how many properties you can afford to rent in each neighborhood.

The LA Times map automatically calculates how many properties you can afford based on 30% of your annual salary being spent on rent and utilities. If you can afford to spend more than 30% of your salary then you can adjust the percentage using a slide control. The map will automatically update to show how many properties you can afford in each zip-code area.

The map uses data from the real-estate website Zillow. The current data is based on rental rates advertised in July and August of 2019, however the data is regularly updated with the latest rents on Zillow. The utility costs are based on averages estimated by the California Public Utilities Commission.

The World's MegaCities

The biggest city in the world is Tokyo, with a population of  38 million. Or it could be Guandong, with a population of 40.5 million. It all depends on which list of the world's largest megacities that you refer to.

Earlier today I linked to a number of maps which allow you to explore population density around the world. However the cities with the most dense populations are not necessarily the cities with the largest populations. The European Commission's Global Human Settlement Layer (GHSL) provides spatial information on the physical size of human settlements and on the population sizes of those settlements. The GHSL Urban Centres Database maps 32 megacities - cities with a population of over 10 million.

On the interactive map if you select to view the 'Urban Centre Database' and then 'Visualization' from the two drop-down menus you can view the most populated cities in the world. Beneath the map you can select to filter the cities shown by the size of their population. According to the map there are 32 megacities around the world with a population over 10 million. In the USA this includes Los Angeles (14,281,720) and New York (15,950,674). However LA and New York aren't the biggest cities in North America. That honor goes to Mexico City (19,559,564).

One problem with determining the population size of cities is how you define their borders. Which is probably why there is a large discrepancy between the populations sizes of cities given in the GHSL and Wikipedia's list of Megacities. Wikipedia lists Tokyo as the biggest megacity in the world with a population of 38,140,000. The GHSL says Tokyo has a population of 33,028,731, quite a long way behind the 40,589,878 population that the GHSL says lives in Guandong. Wikipedia list Guandong as their sixth largest city, with a population of 25,000,000.

The top 5 megacities with the largest populations according to Wikipedia are:

1. Tokyo (38,140,000)
2. Shanghai (34,000,000)
3. Jakarta (31,500,000)
4. Delhi (27,200,000)
5. Seoul (25,600,000)

The UN has a completely different list. Their top 5 (according to this MSN list) is:

1. Tokyo (37,500,000)
2. Delhi (28,500,000)
3. Shanghai (25,600,000)
4. São Paulo (21,700,000)
5. Mexico City (21,600,000)

French Population Towers

Population Données Carroyées is an interactive map showing the population density of France. The map uses 3D towers to show how many people are living in each 200 x 200 meter square.

On the map the height and color of each square relates to the number of inhabitants living in that 200 x 200 meter square. If you hover over a square you can view a breakdown of the local population by age. It would be even more useful if the map also provided an option to change the color of the 3D towers to visualize the population density of different age-groups. The map could then be used not only to view the overall population density but the population density of different age-groups within individual towns and cities in France.


You can compare the population density of France with other European countries on the EU Population 2011 by 1km Grid interactive map. This map shows a finely detailed view of European population density at the 1 km square level. You can also hover over individual 1 km squares on the map to view the total number of people living in that square.

If you are interested in the population density of the world as a whole then you can use the SEDAC Population Estimator (GPWv4). This interactive map uses NASA's Earth Observing System Data and Information System (EOSDIS) data to show where the world's population lives. The SEDAC Population Estimator map includes a tool to draw an area on the map to see an estimate of the population that lives within your selected area.

Mapping the Paranormal, the Weird & the Wonderful

liminal.earth is an interactive map of 'strange, wonderful, unusual, and unexpected' stories. Using the map people can submit locations where they have had weird and strange experiences. These could be encounters with fairies or ghosts, close encounters with time travelers or aliens, or even an unexpected meeting with a witch or wizard.

The stories posted on the map are organized into a number of different categories. These categories include (but aren't limited to) visions, time distortions, ghosts and UFOs.

Perhaps the weirdest thing about this map is that it uses the Google Maps API. For those of you too young to remember - in the olden days most interactive maps were powered by the Google Maps API. However one day Google killed the API by charging excessive fees for its use. Somehow liminal.earth has managed to reanimate the Google Maps API. Now that is paranormal.


The UFO Sightings Map plots over 90,000 reports of UFO sightings since 1905. The map uses data from the National UFO Reporting Center. UFO sightings are shown on the map using scaled map markers. The size of each marker relates to the number of eye witnesses. If you select a marker on the map you can actually read the witness reports. Many of the reports are accompanied by videos or pictures recorded by the eye witnesses.

UFO Stalker has been mapping the locations of the latest UFO reports to MUFON (the Mutual UFO Network) for a number of years. This map includes a number of filters, which allow you to filter the aliens on the map by date and the type of close encounter. If you click on a map marker you can read the event details of the reported sighting. It is also possible to search the map by location and date and view the latest reports in list format.


The world is full of frightening ghosts, monsters and mythical creatures. For example Russians are haunted by the skeletal form of Koschei the Deathless, the legendary kidnapper of young women. In Guatemala you need to keep a wary eye out for Jaguar, the God of Fire, with his pointy fangs and catlike ears. In Denmark you don't want to accidentally bump into the Huldufolk, a race of elves who are responsible for local landslides and crop failures.

You can find all these monsters and many more on this Fantastic Folklore and Magical Myths map. Just click on all the monster shaped markers on this map to learn more about the fantastical creatures of the world.

Mapping the Risk of Flooding

Riesgo is an interactive map which visualizes the flood hazards of Marikina City in the Philippines. Marikina City lies on the Marikina River in a valley between the Sierra Madre mountains and the Quezon City hills. The city therefore lives with an almost constant threat of flooding.

The Riesgo interactive map was created as a way to showcase some of the research undertaken to examine suitable areas for flood evacuation centers in Marikina City. That research project explored elevation data, existing hazard maps and existing evacuation centers. The new map uses that data alongside data on population density, the location of critical buildings and road data to identify flood hazards in the city and to identify areas which are most suitable for the placement of new evacuation centers.

All the data used to assess flood risk and to assess the most suitable locations for evacuation centers could have been overwhelming for the map users. However Riesgo uses the story map format to lead the user through this data step by step. The result is a very effective visualization and explanation of the flood risks in Marikina City and how the city could address those risks. In fact Riesgo is so effective that it not only won the Grand Prize in Mapbox's VizRisk 2019 Challenge but also won the Best Interaction Design category as well.

You can learn more about how the map was made with Mapbox GL and ReactJS in Flooding in Marikina City: A Case Study. This blog post also includes a link to explore the map's code on GitHub.

One Season in One Year

The citizens of Florida Keys experience very little temperature change throughout the year. In fact the temperature only ranges from around 68°F in January to 83°F in August. If the people of Florida Keys want to experience real changes in temperature then they should move to northwest Minnesota, which has the largest difference between the highest and lowest monthly average temperatures in the USA. In some parts of northwest Minnesota that temperature ranges from 3°F in January to 68°F in July.

In Where the Seasons Are Mike Bostock has used National Climatic Data Center records on U.S. temperatures (from 1895 to the present) to map out the difference between the highest and lowest monthly average temperatures across the contiguous United States. On the map regions of the U.S. are colored to show the difference between the lowest and highest temperatures experienced in a year. The green areas on the map experience the lowest differences in temperature between winter and summer. The pink areas have the biggest temperature changes.


If you are interested in the actual average temperature in a state over a year then you can refer to Temperature Sensei's Temperature and Weather Conditions of the World. This collection of weather maps includes a map showing the average temperature recorded in ​each state.

Minnesota on this map experiences an average yearly temperature of 41.2°F. Our friends in Florida Keys can look forward to an average 70.7°F over the course of an average year. Temperature Sensei has also created maps which show the average rainfall and snowfall experienced by every state in an average year.

The Annual Fall Foliage Map

I've caught my first sighting of the Smoky Mountain Fall Foliage Map, the traditional sign that summer is finally slipping into autumn. Every year Smoky Mountain releases their interactive Fall Foliage Map, which plots the annual progress of when leaves change their colors across the United States.

The 2019 Fall Foliage Map has now arrived. According to the map some parts in the north will be seeing a change in leaf color in the next two weeks. The Fall Foliage Map uses historical weather records from all 48 continental states to predict the arrival of fall at the county level across the contiguous United States. The map includes a date control which allows you to view the leaf color you can expect for any date from the beginning of September to the end of November.

The map is accompanied by a chart which shows the average US temperature since 1990. It is also accompanied by an explanation of why leaves change color in the Fall and why leaves actually do fall from the trees in Autumn.

How Healthy are the Dutch?

Nearly half of the residents of the Binckhorst neighborhood in the Dutch city of The Hague still smoke cigarettes. This is twice as high as the national average. The main reason for the still high rate of smoking in the area is probably because it used to be the home of the Caballero cigarette factory. You can view the smoking rates of all Dutch neighborhoods on a new interactive health map of the Netherlands.

Dutch newspaper De Volkskrant has mapped out the results of a large health survey of 457 thousand adult Dutch residents. How Healthy is Your Neighborhood includes an interactive map which allows you to explore the results of the survey across the whole of the Netherlands. Using the map you can view the answers given by Dutch people to their levels of smoking, drinking, levels of anxiety & depression, and other questions about their health.

The map includes a filter control which allows you to highlight areas with vary high levels of health concern. Adjust this slide control and you can highlight on the map only those neighborhoods which score over a selected percentage (of your chosen health metric). You can also hover over individual neighborhoods on the map to reveal the exact estimated percentage in that area.

The First San Francisco Building Age Map

Parallel's 3D Netherlands Building Ages interactive map has proved very popular this month. In fact building age maps from around the world have been popular for the last few years on Maps Mania. However despite their ubiquity I have never seen a building age map of San Francisco.

Until now that is.

Danny Yang has created what could very well be the first San Francisco Building Age map. According to Danny the main reason that no-one has previously created a map showing the age of San Francisco's buildings is that the city releases open data in land parcel form rather than in the form of building footprints. Therefore to create his building age map Danny had to use the land parcel data to work out the age of individual buildings in the city. Danny's interactive version of the map also includes options to view land use and residential unit density in San Francisco.


Parallel's map of building ages in the Netherlands also includes building height data. The height of buildings isn't included on Danny's San Francisco Building Age map. However, if you are interested in the height of San Francisco's buildings you can refer to the SF Building Height map. On this interactive map individual buildings are colored to reflect their height. You can also hover over individual buildings on the map to view their exact height in feet.

Mapping Early Philadelphia

Earlier this month I wrote about the Birth of Boston interactive map, which uses the historical Clough Land Parcel Map to show Boston's early land parcels and who owned them. Philadelphia has its own historical map of early land owners. The University of Pennsylvania's interactive map, Mapping West Philadelphia 1777, maps the city's land parcels at the time of the American Revolution and reveals who owned them.

One reason why I find these two maps so fascinating is that they reveal the names of some of each cities' earliest residents. For example if we explore the Northern Liberties neighborhood on Mapping West Philadelphia 1777 we find that three of the neighborhood's biggest land owners were John & Mary Dickinson and William Logan.

John Dickinson was one of the founding fathers of the United States and is also known as the 'Penman of the Revolution'. William Logan was the son of James Logan, the first secretary of the Philadelphia colony (serving under William Penn). In his lifetime James Logan also became mayor of Philadelphia, chief justice of the Pennsylvania Supreme Court, lieutenant governor, and acting governor.

One early citizen that you might have heard of was Benjamin Franklin. On the map you can find nine land parcels registered to Franklin. These include what is now known as Franklin Court, on Market Street. This is where Franklin built a house and print shop. Both were demolished in 1812.


The map can also be used in conjunction with other historical sources. For example we can use the Free Library of Philadelphia's Digital Collections to view pictures of these land parcels around the time of this map. For example the picture above shows the Charles Norris Mansion, on Chestnut Street, between Fourth and Fifth. If we refer back to the map we can see that Charles Norris owned nearly half of that whole block.


This picture shows the house of Dr. William Shippen, at 4th & Locust Streets. This land parcel on the Mapping West Philadelphia 1777 interactive map is registered to William Shippen, a practitioner in physick.

If you want to carry out your own research into early Philadelphians then you could search the map for properties owned by the descendants of William Penn. Another interesting area of research would be to explore the influence of the Quakers and the Society of Friends in early Philadelphia.

Biographical Mapping

RambleOn is a very interesting experiment to map the locations mentioned in the Wikipedia entries of historically important individuals. The interactive map uses Natural Language Processing to determine the locations mentioned in Wikipedia entries in order to plot the biographical movements of an individual. The online version on RambleOn currently allows you to explore the life trajectories of famous historical figures who lived in the first half of the 20th Century.

You can search the map for individual notable people by using the search tools in the map side-panel. These allow you to search for famous individuals by nationality, individual Wikipedia country domain, or by name. The online version of RambleOn only allows you to explore the life trajectories of the 20th Century individuals already mapped. However if you download the standalone version, RambleON Navigator, you can also enter the movements of any individual with a Wikipedia entry to map their life trajectory.

To create individual mapped life trajectories RambleOn carries out Natural Language Processing on an individual's Wikipedia entry. This processing identifies dates and locations in a Wikipedia entry. The locations are then geocoded using Nominatim. The dates and geocoded locations are then output to a JSON file which is then read and mapped by the RambleOn interactive map. If you interested in the actual code behind this process then you can explore the project on GitHub.

Mapping the Burning Rainforest

Brazil's National Institute for Space Research (Inpe) uses satellite data to assess the levels of wildfire in the Amazon rainforest. Inpe says that this data shows an 84% increase in wildfires in the Amazon this year over the same period in 2018.

One fairly clear indication of wildfires in the Amazon (and elsewhere) is the concentration of carbon monoxide. When carbon burns it produces water vapor and carbon monoxide. According to NASA in South America there is a strong correlation between carbon monoxide levels and fires, 'When fire counts are high, carbon monoxide is high; when fire counts are low, carbon monoxide is low'.

We can use real-time weather maps, such as Windy, to view current levels of CO around the world. At the time of writing Windy shows that there are very high levels of carbon monoxide in the west of Brazil.


Update: NASA has now released an animated map of carbon monoxide levels in the Amazon region from Aug. 8-22, 2019. NASA's AIRS Maps Carbon Monoxide from Brazil Fires uses data from NASA's Atmospheric Infrared Sounder (AIRS) instrument, aboard the Aqua satellite to visualize the carbon monoxide levels associated with the fires in Brazil.


The European Union's Earth Observation Programme, Copernicus, provides an interactive map of Fire Activity across the world. This map uses data from the Copernicus Atmosphere Monitoring Service (CAMS). CAMS provides information on atmospheric composition based on both satellite and ground-based observations. The National Institute for Space Research provide a similar interactive map. The Inpe map also includes a fire hazard layer showing the risk of fire across Brazil.

There is a direct link between the increase in wildfires in Brazil this year and the growing deforestation in the Amazon. Of the 10 areas that have recorded the largest fires in 2019, seven are areas with the highest number of deforestation warnings. Last year Brazil elected Jair Bolsonaro. Since Jair Bolsonaro became president the rate of deforestation in the Amazon has grown. This year the rate of wildfires has also grown. Most people around the world believe therefore that this year's increase in fires in the Amazon is largely the direct fault of Jair Bolsonaro. Bolsonaro himself says that non-government agencies are causing the fires in order to embarrass him. He also recently fired the head of Inpe.

Between a Wall & the Syrian Army

In Syria hundreds of thousands of civilians are trapped between the concrete border wall with Turkey and approaching Syrian and Russian forces. Eight years after the start of the civil war in Syria fighting is now mainly limited to the north-western province of Idlib, the last stronghold of rebel forces. As the Syrian and Russian forces approach the border fleeing civilians have become trapped against the border wall which has been constructed between Syria and Turkey.

Reuters' article Syrians at the border with Turkey await wars bitter end includes a number of maps which help to illustrate the plight of the civilians desperately being caught up in Russia and Syria's violent attacks. Over recent weeks the Russian and Syrian forces have been launching continuous air attacks on the province of Idlib. The government forces have also been burning orchards and crops. The maps in the Reuters article show the damage being caused by Syrian government and Russian airstrikes on civilian targets, including schools and hospitals.

The maps also show where agricultural fields have been burnt, destroying crops such as wheat and barley. Orchards and olive groves have also been destroyed by government incendiary weapons. Reuters says that in some areas over 30% of cropland has been destroyed. The result has left the fleeing civilians trapped in Idlib with escalating food prices and little to eat. 76% of the civilians trapped against the border with Turkey are women and children.

Building America's Transcontinental Railway

At the same time as the American railroads were being constructed in the Nineteenth Century the new technology of photography was also being developed. The railroads made good use of this new technology to document and promote their drive to build routes from the east to west coast. Which is why the Library of Congress has been able to combine vintage maps and photographs in this story map exploring the construction of America's transcontinental railroad in the years 1863–69.

As you progress through the Camera and Locomotive story map you can view the vintage pictures captured by a number of different photographers in the construction of the railroad. A number of different maps are used, including a couple of vintage maps, to show the route that the rail companies used to build a transcontinental railway. On these maps colored markers are used to show the location of the geotagged vintage photos. The colors of these markers reflect the different photographers who captured each picture and you can click on the individual markers to actually view a photograph.

After the Pacific Railroad Act of 1862 the Central Pacific Railroad and the Union Pacific Railroad led the race to link the east coast to the Pacific. The early photographs in the Library of Congress' story map both document the work of these two companies and help reveal the beauty of the difficult terrain that they railroad companies were trying to conquer.

Who is Still Smoking?

Despite the rise of vaping it appears that many Europeans still like to smoke. According to World Health Organization data, despite the dangers to health, smoking rates are still very high in many countries around the world. However it also appears that in many countries women are paying more attention to the dangers of smoking and are actually giving up quicker than men.

Smoking is more prevalent in Europe and the Western Pacific region is an interactive cartogram which shows smoking rates across the globe. Don't be confused by the size of the countries on this cartogram as they are actually scaled by their population not their smoking rate. This means that the larger squares do not represent the countries with the highest rates of smoking. The smoking rate in each country is actually visualized by the color of the countries. The darkest colored countries on the map are therefore the ones with the highest smoking rates.

Some of the countries with very high rates of smoking (including Peru, China, Indonesia and Egypt) actually have very low rates of smoking in the female population. This is presumably a result of prevailing sexist expectations in these countries about how females should behave. It also means that the smoking rates among the male populations in these countries is incredibly high.


Although the vast differences in smoking rates between men and women in some countries is a clear result of inherent sexist attitudes it is also true that the smoking rate for women has fallen in almost every country since 2000. This interactive chart (using the same WHO data on global smoking rates) shows where smoking rates have increased and decreased for both men and women. The chart shows that there are only two countries in the world - Russia and the Czech Republic - where the smoking rate for women has actually increased while, at the same time, decreasing among men. On the other hand there are ten countries where the female population has decreased its smoking rate at the same time as men have increased their rate of smoking.

The good news is that in the majority of countries around the world both men and women have decreased their smoking rates.

These interactive smoking rate cartograms and charts were created using the Datawrapper data visualization platform. The tool can be used to create charts, tables and map from your own data. You can explore other data visualizations created with Datawrapper on River, Datawrapper's showcase of visualizations created using its platform.

Iran and the Strait of Hormuz

The United States, the United Kingdom and Australia have all now sent ships to help protect international shipping in the Strait of Hormuz. Twenty percent of the world's oil is shipped through the Strait of Hormuz. Iran has been accused of sabotaging tankers in the Strait and last month seized a British oil tanker which it claimed had strayed into its waters. In June Iran also shot down a US military surveillance drone which they said had entered Iranian airspace.

The Conversation has released an interesting story map which does a good job of explaining the current tensions in the Strait of Hormuz. The Conversations' article, The Strait of Hormuz is the most important oil choke point in the world, includes an interactive map which explores some of the recent incidents in the Strait and the planned response by the US-led naval mission.

The map only covers the recent incidents in the Strait of Hormuz. What it doesn't do is look at the background reasons for Iran's recent aggression. These go back to Donald Trump's decision last year to withdraw from the nuclear deal which the US (and other world powers) had signed with Iran. Since then the US has imposed sweeping sanctions against Iran and increased its military presence in the region. Iran has not reacted well.

How Far is a Mile?

One thing I nearly always omit from the interactive maps I create is a distance scale. This could be a big mistake. It turns out that most people are pretty bad at estimating distances on maps. Including me.

You can find out how good you are at estimating distances on a map using this Distance Perception Study interactive map. The map simply asks you to draw a circle with a radius of one mile on a location that you are familiar with. When you have submitted your circle you are then told how accurate your circle was.

When I attempted to draw a one mile circle centered on my house I was way out. The circle I drew was actually 0.72 of a mile. So I therefore underestimated the distance of a mile by more than 25%. This is embarrassing - but on the plus side - my favorite pub is actually a lot nearer than I always thought it was.

If you attempt the study yourself you might actually be asked to draw a circle that represents a 5 minute walk or a circle that represents a 5 minute drive rather than draw a circle that represents a mile. The study asks at random one of these three distances.

The Distance Perception Study map is actually part of Dave Michelson's research project for his Masters of Liberal Arts and Sciences. You can read about some of his initial findings from the study at Can Users Estimate Distance on Web Maps? According to the results so far it turns out that I am not alone in underestimating the length of a mile on an interactive map. On average participants in the study have underestimated the distance of one mile by 1,486 feet.

Mapping America's Area Deprivation Index

The Area Deprivation Index (ADI) is a measure of neighborhood disadvantage compiled by the University of Wisconsin School of Medicine and Public Health. The index ranks neighborhoods based on data taken from the American Community Survey Five Year Estimates. The ten ranks in the index consider local measures of income, education, employment, and housing quality.

You can view the ADI scores at census block levels on the Neighborhood Atlas interactive map. On the map each block is colored to show its ADI rank. There are ten ranks in the ADI ranging from the least to most disadvantaged. You can click on individual blocks on the map to see in which ADI decile it ranks. If you are interested in viewing the distribution of different ADI deciles then you can hover over individual decile colors in the map legend. This will filter the map to only show the blocks in the selected decile.

Census blocks can be ranked on the map relative to the whole country or to other neighborhoods in the same state. You can switch between the state-only deciles and the national percentiles by using the menu in the map legend.

Europe Stinks

OdourCollect is an interactive map which is dedicated to recording the smells of the world. The map is part of a citizen science project to build an odour map of the world. Apparently, after noise complaints, bad smells are responsible for the second most environmental complaints across the globe. OdourCollect has been designed so that it can be used by communities which are affected by bad smells to systematically record and report the extent of bad odours.

Using OdourCollect five different categories of smell can be recorded simply by clicking on a location on an interactive map. These categories include waste, agricultural and food smells. The strength of these individual smells can be recorded, from very weak to extremely strong. The pleasantness of a smell can also be noted, using a scale from -4 (if the odour is really unpleasant) to +4 (if the odour is very nice).

Of course Europe isn't the only place on Earth which has distinctive odours. OdourCollect is running ten initial pilot projects in Spain, Portugal, Greece, Bulgaria, Chile, Italy, UK, Germany, Austria and Uganda. However the application is already being used by people to map smells around the world. In fact the map already has smells reported in Africa, Asia, North & South America and Europe.


OdourCollect is not the first interactive map of smells. Back in 2015 Rossano Schifanella created three Smellscape maps plotting the dominant smells in three global cities. His three maps New York Smellscape, London Smellscape (the London map no longer seems to work) and Barcelona Smellscape colour individual city streets based on their dominant smells.

These smell maps were created by using smell related tags added to Flickr photographs of locations in the three mapped cities. Each street segment on the individual maps is coloured to reflect the most characteristic smell tagged in that area. Unfortunately Rossano's maps now don't seem to load the underlying map tiles. The maps also don't have legends, so we also now have to guess what smells the individual colours on the maps represent.

Mapping the English Premier League

Sky Sports has mapped the birthplaces of all 557 football players registered to clubs in the English Premier League. According to Transfermarkt 368 of those 557 players were born overseas,

In Where were Premier League players born? Sky has plotted the birthplace of every single player in the EPL. If you click on the markers on the map you can learn more about the individual players, such as which position they play and their number of Premier League appearances and goals. You can also filter the map to show only players for individual clubs by clicking on the club logos above the map.

The map reveals that Europe is by far the biggest catchment area for EPL teams. However a lot of players also come from South America and Africa. There are few players in the EPL who originate from Asia, North America or Oceania. I can't help wondering if the map might therefore be a reasonable guide as to where in the world children grow-up playing football.

Sky's map is in truth a pretty poor attempt at visualizing the data on EPL players. If you want to know how many players come from individual countries then you need to zoom-in on the map and count the players yourself. This can be difficult, especially when two or more players were born in the same city or when players were born very close to country borders. Would it have been that difficult to provide a table view with the map?

The Dot Map of American Education

Educational Attainment in America is a dot map which visualizes the level of education achieved by the American population across the whole United States. Using the map you can zoom in on any town or city and see the local distribution of educational attainment.

The map shows five levels of educational attainment ranging from those who didn't finish high school to those with graduate degrees. As you can see in the screenshot above the map reveals the often quite stark differences in educational achievement which can exist in different neighborhoods, even in the same cities and towns. You can examine the distribution of any of the levels of educational attainment by selecting any combination of the five levels of achievement (click on the levels in the map legend to add or remove them from the map).

The map also includes an option to view a chart of the percentages who have achieved different levels of achievement in the current map view. This is very useful for comparing the different levels of achievement in different neighborhoods or cities. For example if you zoom-in on Manhattan you can see a very high percentage of the local population holds some kind of college degree. Conversely zoom-in on the Bronx and you find that the largest percentages of educational achievement are high school & less than high school and a far smaller percent of the population has achieved a degree level of education.

Burning the Amazonian Rainforest

Fires in the Amazon have grown by an horrendous amount this year. Satellite imagery from NASA show a 65% increase in fires in Brazil since the beginning of 2019, when compared to the same period in 2018. There is a direct link between the fires and deforestation in the Amazon. Of the 10 areas that have recorded the largest fires in 2019, seven are areas with the highest number of deforestation warnings.

Infoamazonia's Fire map is a visualization of historical forest fires in the whole of Latin America. The map clearly shows that the most intense and frequent fires have been in the Amazon rainforest. Recently the regions of Acre and Amazonas have both declared a state of emergency because of the levels of smoke from wildfires. August and September are historically the worst months for wildfires in the Amazon so the situation is expected to become worse in the coming months.


In the last few years Brazil had actually experienced a fall in wildfires. However last year Brazil elected Jair Bolsonaro. Since Jair Bolsonaro became president the rate of deforestation in the Amazon has grown. This year the rate of wildfires has also grown.

If you are struggling to understand the rate and the scale of deforestation in the Amazon then you can use the Real-Time Amazon Deforestation interactive map. This map allows you to compare the size and rate of deforestation in the Amazon with your own neighborhood and city. When you share your location with the map a circle begins to expand on the map showing how much of the Amazon is lost in 1 minute, 1 hour, 1 day, 1 month etc.

Greta Thunberg's Real-Time Map

Greta Thunberg is just about half-way through her two-week journey to the United States. The young climate activist is crossing the Atlantic by solar-powered yacht in order to attend the Climate Action Summit in New York on 21-23 September.

You can follow Greta's journey on a real-time interactive map. Team Malizia shows the real-time position of the yacht Malizia II as it crosses the Atlantic. The map includes the track of the yacht's journey so far from Plymouth in the UK and Greta's Tweets and photos taken during the crossing. Thanks to an animated wind layer you can also view the wind directions and speeds in the Atlantic in real-time.

The journey from the UK to New York is over 3000 nautical miles and the journey will take around two weeks. The Malizia II does have an emergency combustion engine in compliance with IMOCA rules but the engine will not be used during the journey. Electricity on the yacht is generated by solar and hydro power. These two energy sources are capable of providing more electricity than the yacht actually needs. Therefore the journey will be fully emission free.

The Malizia II is a racing yacht and is therefore kept as light as possible. This means the yacht has no toilet, shower, cooking facilities or proper beds. The two week journey to the USA won't exactly be a comfortable experience for Greta or the crew.

1% of the World Lives Here

If you've ever visited Map Porn on Reddit you will do doubt have seen the endless maps which highlight the most densely populated areas of a country and which have a title along the lines of '...% of this country lives here'. These maps can be quite interesting but on the whole their ubiquity is a little tedious.

Having said that I do really like this World Population 3D globe. Spin this globe around and the red dot will shrink or grow to show you where 1% of the world's population lives in the current map view. Move the globe over Siberia and the red circle grows to cover half of Russia. Center the globe over India and the red dot shrinks to just a small speck on the map.

You can adjust the percentage of the population shown within the red circle simply by using the slider control bar provided. One thing the map misses is an underlying layer showing population density. However if you switch to the night view you can see a night light layer, which does provide a very rough idea of population density across the globe.


Last year The Pudding created an impressive interactive map which visualized 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 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.

For example The Pudding compares the pyramid population maps of some European cities to Kinshasa, DRC. In Kinshasa poor transportation infrastructure has led to a densely populated city center, whereas European cities tend to have less densely populated centers and more densely populated suburbs. Because of poor transportation in Kinshasa the population pyramids in the city center fall sharply away, while in European cities there tends to be a more gradual slope from the center out into the suburbs.

The Proper Pronunciation of Placenames

Have you ever experienced the embarrassment of mispronouncing the name of a town or city while traveling abroad? Well you now no longer have to worry about how a difficult place-name should be pronounced. Using the Spoken Word interactive map you can now just simply click on a location to listen to the place-name being spoken by a native speaker.

The Spoken Word was created by Michael McNeil for his masters degree at the University of Kentucky. The map uses recordings from Forvo to provide clips of native speakers pronouncing place-names around the world. Forvo is an online pronunciation reference website. The site compiles recordings of pronunciations for words in different languages. These recordings include the pronunciations of place-names around the world.

The Spoken Word is a great idea for an interactive map. However I think the map could be improved by simply replacing the markers on the map with the actual place-name labels for each location. This would be an easy enough task in Mapbox. You could even use a different color for these labels so that these locations couldn't be confused with the underlying place-name labels on the map.

A Game of Hungarian Thrones

Tomorrow Hungary will celebrate St. Stephen's Day. The day commemorates the foundation of the Hungarian state. On this day Hungarians remember Stephen I, the first king of Hungary and founder of the Kingdom of Hungary. St Stephen became king of Hungary in 1001. For the following 917 years Hungary was ruled by a succession of monarchs, until Charles IV renounced participation in state affairs in 1918.

You can explore the history of Hungary's royal kings and queens on Atlo's Battle of Thrones. This detailed history of the Hungarian royal families includes a number of data visualizations including family trees and an interactive map. The map shows the places where each of Hungary's royal rulers was born and died. It reveals that the Hungarian royal family have originated from all across Europe. In fact even the second king of Hungary, Stephen I's successor, Peter of Venice, was born in the Republic of Venice (he wasn't the only Hungarian king born in Venice - Andrew III was also a native of the republic).

Other Hungarian kings have been born in what is now Spain, Romania, Italy, Germany, Poland and  elsewhere across the continent. On the map the red circles show where a monarch was born and the blue circles indicate the monarch's place of death.

The 3D Building Age Map

Bert Spaan's Netherland's Building Age Map, created for the Waag website, is one of my favorite interactive maps of all time. This map visualizes the age of a staggering 9,866,539 buildings in the Netherlands. This is very impressive in itself but its use of distinct colors for buildings of different construction ages means that the map also has a striking visual impact.

Inspired by Spaan's map Parallel has created a Netherlands Building Ages interactive map which shows not only the age of 10 million buildings in the Netherlands but the height of those buildings as well. This map makes use of Mapbox's GL extrude property to visualize the height of all the buildings in 3D. The colors of the buildings indicate their age. You can also hover individual buildings to learn a building's exact year of construction.


The map team at the City of Amsterdam used the same Construction and Address Database (BAG) used in the above two maps to create an animated map of the construction of Amsterdam over time.

Amsterdam Growing Over Time is an incredible animated map which shows how the city of Amsterdam has developed and grown from a few houses in the 17th century into the dynamic city it is today. Click on the play button and you can watch as the city's building footprints are added chronologically to the map based on each building's age.

Some of the buildings in the BAG database are obviously newer buildings which have been built in the same location and which replaced older buildings. The map therefore doesn't provide an exact picture of how the city developed. However Amsterdam has enough historical buildings still standing for the animated map to provide a reasonable overview of how Amsterdam has grown over the centuries.

Using Mapbox's extrude property it would be possible to create an animated map of Amsterdam which showed the buildings of the city growing out of the map over time. This sort of historical animated map might be even more impressive in somewhere like New York, a city where there are much taller buildings. Imagine an animated map of New York during the 20th Century showing the city's skyscrapers emerging from the map and growing ever taller over time.

Coral Bleaching of the Great Barrier Reef

Since 1981 the Great Barrier Reef has suffered from four major mass bleaching events. Bleaching happen when very high sea temperatures cause the coral to release the colorful algae that lives inside its tissue. The algae is extremely important for the health of the coral. Without the algae the coral starves. In 2016 93% of the Great Barrier was effected by coral bleaching.

Carbon Brief's Can the Great Barrier Reef survive climate change? includes an interactive story map which looks at the Great Barrier Reef's four bleaching events since 1981. As you scroll through Carbon Brief's story the map updates to show the extent of the barrier reef effected by each of these four bleaching events.

Coral bleaching happens when sea temperatures rise. A rise in temperature of 1 degree Celsius above average can cause bleaching. Because of global heating severe coral bleaching is five times more frequent now than it was 40 years ago. Carbon Brief's report explores how coral bleaching has a knock on effect on many other species which rely on the coral reef to survive. It also explores how warmer sea temperatures effect the coral's ability to reproduce.

3D Terrain Mapping

Vladimir Agafonkin, the creator of the Leaflet mapping platform, has released a JavaScript library for real-time terrain mesh generation from height data. MARTINI allows you to render terrain in 3D.

MARTINI builds a 3D terrain using Right-Triangulated Irregular Networks (RTIN). Check out this MARTINI: Real-Time RTIN Terrain Mesh Observable notebook which both explains what this means and includes a demo map which shows you perfectly how RTIN works. You can zoom in an out and rotate the demo map. You can also adjust the level of precision using the slide control.

The 2D map below the 3D scene also updates in real-time when you adjust the precision of the map. This provides a great visualization of how Martini works as it shows the number of triangles being used at different levels of precision.

Mapping Earthquake Scenarios

The LA Times has released an interactive map which allows you to visualize a number of different earthquake scenarios on top of any California location. To create the map the newspaper worked with the U.S. Geological Survey to identify 14 different significant earthquake scenarios which could strike along California's fault lines.

If you enter a California address into the What would a powerful earthquake feel like where you live? interactive map you can view the likely effect of an earthquake at your address. The map is colored to show the extent of shaking that could be felt around the epicenter of a quake. The map also provides an assessment of the cost of the possible damage, the number of lives which could be lost and the number of non-fatal injuries.

The map shows the worst of the 14 scenarios for your address. This isn't necessarily the worst earthquake which could happen. The USGS has actually modeled 300 scenarios for the California area. For reasons of speed the LA Times map only uses 14 of these scenarios.


The OpenQuake Map Viewer provides free and open-source visualizations of global earthquake hazards. Each of the Map Viewer visualizations uses the OpenQuake engine, a seismic hazard and risk calculation software, to show seismic risks & hazards and seismic exposure around the world,

Currently the OpenQuake Map Viewer provides three separate interactive Leaflet powered maps: the Global Seismic Hazard Map, the Seismic Risk Map and the Global Exposure Map. The Global Seismic Hazard Map shows the potential for seismic activity based on hazard and risk calculation models. The Seismic Risk Map visualizes the average annual cost of seismic activity around the world. The Global Exposure Map is a visualization of the built areas of the world.

The Global Seismic Risk Map can provide individual country seismic risk assessments. Click on a country on the Risk Map and you can view details on the annual cost of seismic activity for residential buildings, commercial buildings and  industrial buildings. You can also download the full OpenQuake profile for any country.

Berlin: The Divided City

They may have torn down the wall but Berlin remains a city painfully divided - by football. In the eastern red half of the city live the faithful supporters of FC Union Berlin. In the opposite, western blue half of the city reside the fans of Hertha BSC.

Last season FC Union Berlin secured their first ever promotion into the Bundesliga. The result is that this season Berlin will have two football teams playing in the Bundesliga and support for the two teams is split fairly evenly across the city. You can see how support for the two Berlin Bundesliga teams divides the city on a new interactive map.

The Berliner Morgenpost's Fußballkarte map shows which of the two Berlin football clubs have the most members in each postcode area. If you mouse-over a postcode area on the map you can view the actual number of members in the area for both teams. In truth, as the more established Bundesliga club, Hertha BSC (36,930) has more paid-up members than FC Union Berlin (29,043).

If you live in Hamburg then you have no need to feel left out. Hamburger Fußballkarte is an interactive map that visualizes where HSV and St. Pauli have the most fans in the city of Hamburg. German football fans might also like the Berliner Morgenpost's Fußballkarte (Beta) map. This map shows the geographical support for most of Germany's top football teams across the whole country. The map was created back in 2014 so the data might be a little out of date.

Right Whale Spotting

The NOAA Right Whale Sighting Advisory System is an interactive map of right whale sightings in the North Atlantic. The system has been designed to help reduce collisions between ships and the critically endangered North Atlantic right whale.

Using the map mariners can see where right whales have most recently been sighted off the east coast. The map includes a tool which allows you to see all the right whale sightings made in the last two weeks. Alternatively you can select to view whale sightings for any selected date range.

If you want to view the location of right whales spotted in the last two weeks in Canadian waters you can visit the WhaleMap. The WhaleMap shows both confirmed sightings of right whales and whales which have been detected acoustically. On the map the black markers show sightings of whales, while the red markers show right whales which have been acoustically detected. If you click on these markers you can find out how many whales were spotted at that location and the date of the sighting.

John Snow's Cholera Map in 3D

John Snow's map of cholera victims during the 1854 cholera outbreak in London is one of the most famous examples of effective data visualization. By plotting the homes of cholera victims on a map Snow was able to identify a water pump in Broad Street as the cause of all the local cases of cholera. Snow's map essentially proved that cholera was spread by contaminated water and disproved the prevailing miasma theory, which believed that diseases like cholera were transmitted by bad air.

Creating an interactive version of John Snow's original map has become something of a rite of passage in the field of cartography. However it is rare for any of these attempts to bring anything essentially new to John Snow's visualization. John Snow Cholera Map 2D-3D does offer something different. This map allows you to switch between a digitized version of John Snow's original map and a 3D version of the map. On this 3D view Snow's black dots (indicating where people have died from cholera) become vertical stacks. These vertical stacks provide a clearer picture of the exact location of the households that experienced multiple deaths.

Cholera & Elevation

In developing his theory that cholera was transmitted by water rather than air Snow was able to use the detailed statistics of William Farr. In 1838 Farr, a qualified doctor, was appointed to the General Register Office. This was the government department responsible for recording births, deaths and marriages. In his role at the General Register Office Farr was able to introduce a system which recorded causes of death. This data could then be used to look for geographical, environmental and occupational patterns in death rates and different diseases.

It was partly Snow's use of these death rate statistics which led him to believe that cholera was caused by germs which were transmitted by water. William Farr was impressed with Snow's germ theory of cholera being transmitted by water. However Farr himself believed that cholera was more commonly transmitted by air (the miasma theory). He even developed his own theory based on the idea that deadly miasmata are greater at lower than higher elevations. In his 'Report on the mortality of cholera in England 1848-49' Farr's detailed analysis of the distribution of cholera deaths in London actually established an apparent link between the rate of cholera deaths and elevation.


In this map from the report the red numbers 'denote the elevation in feet above the Trinity Highwater Mark' (image from the Wellcome Collection). Farr believed that the link between elevation and cholera was further evidence for the miasma theory. In 1854 Farr was a member of the Scientific Committee for Scientific Enquiries in Relation to the Cholera Epidemic of 1854. A committee which rejected John Snow's Broad Street pump analysis. The report concluded that "on the whole of evidence, it seems impossible to doubt that the influences, which determine in mass the geographical distribution of cholera in London, belong less to the water than to the air."

William Farr however was finally persuaded of Snow's germ theory of cholera and its waterborne transmission. In 1866 Farr himself wrote a report, which included detailed analysis of death statistics, to show that water and not air transmission was the most important cause of cholera.