Tuesday, September 27, 2022

How Well Do You Know Your Boundaries?

You can find out how well you know the extent of your neighborhood by playing Axios' new interactive boundary drawing game. In Draw Your Neighborhood you are asked to draw an outline on a map to show where you think your neighborhood boundary lies. Once you have drawn the boundaries for a few of your city's neighborhoods you can compare how well your local knowledge compared to other Axios readers. 

There are twenty U.S. cities to play in Draw Your Neighborhood, including San Francisco, Philadelphia, Dallas and Chicago. After you select a city you are then asked to draw on an interactive map the boundaries of five city neighborhoods. When you have drawn all five you can view a map showing the average boundary for each neighborhood (as drawn by other players) and are given a percentage score for each neighorhood indicating how different your guess was from the average. 

If your neighborhood isn't one of the twenty cities featured in Draw Your Neighborhood don't worry. You can make your own interactive Draw Your Neighbohood map by cloning my Where is Texas map. To make your own map simply click on the fish icon and select 'Remix on Glitch'. You can then change the instructions to ask people to draw any neighborhood in the world. Every time someone draws on your map the boundary will be added (in GeoJSON format) to the map side panel. 

Annotating Vintage Maps

At the weekend I released an annotated translated version of the Borgia Mappa Mundi, a German map of the world which was made around the middle of the 15th Century. This annotated version of the map was very easy to make using my Leaflet-IIIF-GeoJSON web application.

Leaflet-IIIF-GeoJSON allows you to view and annotate IIIF images in a Leaflet.js interactive map. 

With Leaflet-IIIF-GeoJSON you can: 

  1. View IIIF images inside a Leaflet map 
  2. Use the provided drawing tools to then annotate the image 
  3. Save your annotations as a GeoJSON file 
  4. Load and view GeoJSON data on top of any IIIF image 

Demo - this will open a blank copy of Leaflet-IIIF-GeoJSON. 

If you want to view an image with Leaflet-IIIF-GeoJSON you need to append the URL of a IIIF manifest to the URL of Leaflet-IIIF-GeoJSON. For example, 


 will open The Drawing Lesson by Jan Steen inside Leaflet-IIIF-GeoJSON.

You can view more examples of Leaflet-IIIF-GeoJSON in action on its GitHub page. The Leaflet-IIIF-GeoJSON GitHub repository also includes a number of demo geojson files which you can dowload and view on Leaflet-IIIF-GeoJSON.

IIIF is a standardized method of describing and delivering images over the web. It is a standard for creating interactive image tiles for images of documents, manuscripts, photographs and paintings. Many major art galleries, museums and universities around the world are adopting the International Image Interoperability Framework (IIIF). This means that there are thousands of porential sources for IIIF images which you can view in Leaflet-IIIF-GeoJSON.

One major source for vintage maps to view in Leaflet-IIIF-GeoJSON is the David Rumsey Map Collection. In the screenshot above you can see how to retrieve the IIIF manifest image for a map in the David Rumsey Map Collection by selecting Share > IIIF Manifests.

Once you have copied the IIIF manifest address of a map on the David Rumsey website you can simply append it to the Leaflet-IIIF-GeoJSON URL. For example,


will open a geological survey map of the United States. Now you can draw and annotate the map in Leaflet-IIIF-GeoJSON and save the results as a GeoJSON file.

Monday, September 26, 2022

What Four Words

The global addressing system What3Words has been receiving a lot of free publicity, thanks to its use by the UK government's Department for Digital, Culture, Media and Sport. The department's tracking website for the 'Queue' (the line of people queuing to visit the Queen's coffin), used W3W in order to provide an updated record of where in London people could join the end of the line. Unfortunately a lot of that publicity was very negative.

If you want an alternative to What3Words you can now use the open sourced pataddress global addressing system. This new addressing system allows you to pinpoint any location on Earth using Only4Words. pataddress comes with its own default word database (the words used to describe a location) but also allows you to build your own database with a built-in word frequency analyser.  - via weeklyOSM

There are of course many alternatives to W3W and pataddress. You can use Google's much ignored Plus Codes or even the obscure and antiquated latitude and longitude system. You could even try the iconic  what3emojis or the profane Four King Maps.

Italian Election Maps

Italy appears to have voted in its first Fascist leader since Benito Mussolini. The main winner in yesterday's national elections has been Giorgia Meloni's Brothers of Italy, a party which traces its roots back to Mussilini's National Fascist Party.

Sunday's election saw an historic low turnout of just 63.91% of the electorate. The Right Alliance (consisting of Brothers of Italy, Forza Italia, League and Us Moderates) will now form the next Italian government, having won a majority of seats in both the Chamber of Deputies and the Senate of the Republic.

You can explore the Italian election results on The Guardian's Italian Election 2022: Live Official Results. The Guardian's results page includes an interactive map which shows the winning coalition in each electoral seat. You can hover over individual seats on this map to view a breakdown of the votes cast for the 'Right Alliance', 'Left Alliance', 'Five Star', 'Center Alliance' and 'Other'. 

Corriere Della Sera's Election Results 2022 also includes an interactive map which shows the winning coalition in each electoral district. Both The Guardian's and Corriere Della Sera's maps show that the Right Alliance has been the most popular coalition in seats across the whole country. If you click on individual seats on the Corriere Della Sera map you will be taken to a more detailed breakdown of the results in that seat.

Saturday, September 24, 2022

A 15th Century Map of the World

The Borgia Mappa Mundi is a map of the world which was made around the middle of the 15th Century. The map is orientated with south at the top, differing from earlier medieval mappa mundi and earlier T and O maps which tended to be oriented with east at the top (at least three other 15th Century world maps were also orientated with south at the top - the 1448 world map of Andreas Walsperger, the 1459 Fra Mauro world map, and the Zeitz mappa mundi.

The Borgia map, however, does resemble other early western global maps in that it divides the world into three continents - Asia, Africa and Europe (with Asia being roughly the size of Africa and Europe combined). It also resembles other early western maps in that its view of the world is shaped by the Bible, Ptolemy's Geographia and many dubious myths and legends. 

My annotated Borgia Mappa Mundi is an interactive version of this 15th Century map of the world on which the original German placename labels have been translated into English. This translated version of the map really allows you to explore the world as seen by a 15th Century European. Search hard and you can find the location of Paradise (east of India), the mountains of the moon, and the provinces of Gog and Magog. While exploring the world make sure you also keep a wary eye out for the huge men with horns four feet long (in India), the Ethiopian Saracens with their faces of dogs and the Bavarian stags which vomit boiling water.

The Borgia map used in my annotated map belongs to the David Rumsey Map Collection. The translations come from The Borgia/ Velletri World Map DATE: 1410 - 1458 (PDF) and A Fifteenth Century Map of the World (PDF).

If you like my annotated Borgia map then you might also like Historia Cartarum's Annotated Claudius Map. This provides an interactive annotated map of Matthew Paris's medieval map of Britain, revealing the modern British placenames for all the locations depicted on the original 13th Century map.

Friday, September 23, 2022

The RAF Map of Post-War London

Layers of London is an interactive map which gives you access to lots of historic maps and historical information about the capital city. This morning I've being exploring the Layers of London RAF Aerial Collection (1945-1949).

After World War II the Royal Air Force methodically flew over the whole of Britain to photograph the country from the air. This resulted in 24,000 photographs of London. This aerial imagery provides a stunning visual record of London just after World War II. Bomb damage from the Blitz is clearly visible in lots of the imagery. 

In the screenshot of West Ham above you can clearly see where the bombs fell. The rows of Victorian era terraced housing are interrupted by temporary white prefab buildings (at the center of the image). This is where houses were bombed out during the war. If you walk this neighborhood today you can still easily see where the bombs fell. If any building was clearly built after World War II then you can be sure it was built on the location of a bombed out Victorian era building. 

You can get an even better idea of where German bombs fell on Layers of London's Bomb Damage Map. On this map individual buildings are colored to show the extent of any bomb damage. Buildings colored black on the map were totally destroyed by a bomb. Dark red buildings were 'Seriously Damaged'. Buildings colored green were cleared (presumably as a result of bomb damage).

Thursday, September 22, 2022

The United States of Extinction

The Eastern Elk once ranged across the northern and eastern United States. In the 15th Century the Eastern Elk inhabited the Eastern Woodlands region, as far west as the Mississippi River, in huge numbers. Then the Europeans colonized the United States. By the end of the 19th Century, due to over hunting and the destruction of their natural habitat, the Eastern Elk no longer existed.

The Eastern Elk is of course only one of a number of indigenous species which have been driven to extinction in the United States. The United States of Extinction is an interactive map which highlights just one species in each state which no longer exists. Select a state on this map and you can learn more about one indigenous species of plant, fish, animal or bird which is now extinct.

The United States of Extinction map was created by the Center for Biological Diversity, a charity dedicated to saving species on the brink of extinction.

Of course whole species of animals are not only threatened with extinction in the United States. What is Missing? is a global map and timeline of animal species around the world that have either become or are in danger of becoming extinct. What is Missing? includes both a global map and a timeline view of these animal species. In both the map and timeline view you can select any of the individual markers to learn more about the individual endangered or extinct animal species.

What is Missing? includes a number of videos and stories providing information about some of the planet's most endangered species. It also includes information about actions that you can take as an individual to help protect endangered animals, prevent habitat loss and reduce emissions.

The International Union for Conservation of Nature and Natural Resources's Red List of Threatened Species is a comprehensive database of animal and plant species which are at risk of extinction around the world. 

The IUCN Red List website allows you to search for specific animals or plants and view an interactive map showing where the species still exists in the wild and any protected areas provided for the species. You can use the IUCN Red List search tool to view interactive maps showing the range of any threatened species. Using this tool you can search for a species using either its common or scientific name.

Wednesday, September 21, 2022

The Number of Cars in Berlin

How Many Cars is an interactive map which shows the number of cars in Berlin in April 2019. On the map you can see every single moving car in the city (highlighted in pink) and every parked car (colored blue).

Last year more than 40 volunteers used a custom made map tagging tool to identify all the cars on an aerial image of Berlin. The composite aerial image was captured on the 1st and 6th of April 2019. How Many Cars shows the result of this analysis. At the time of writing the tagging of cars in most of the city center is complete. 

You can access the data itself on the Car Tagging Data page on GitHub.  This repository also includes a number of suggestions for how the data might be used, e.g. for analyzing how much space cars take up, for analyzing informal parking (the number of cars not parked in official parking zones), or the number of parking spaces without parked cars.

Tuesday, September 20, 2022

CSI Suspect Mapping

Feasible Route Mapping is an interactive map that can be used to find out all the possible routes that could be taken from one location to another. The map was designed to be used during criminal investigations to determine all the locations a suspect could have traveled to in a specific time. The map can therefore help investigators to quickly evaluate a suspect's possible movements in and around a crime. 

Enter a starting point and a destination into Feasible Route Mapping and it can calculate the areas that a suspect could have reached within a set time frame, taking into account the suspect's mode of transport. An isocrone map is then displayed which shows the reachable areas. This isochrone layer includes time interval steps which indicate the length of time it would have taken to reach each point in the possible travel areas. 

The map uses the Valhalla open-source routing engine to calculate possible routes and the isochrone layer. The map was created by Mario Širić as part of his master's thesis. You can learn more about the application and view its code on the project's GitHub page.

You can find more examples of visualizing travel time under the Maps Mania isochrone tag.

Monday, September 19, 2022

If the Romans did Data Visualization

If you've ever wondered how the ancient Romans might have visualized population density then you might like Gridviz - Mosaic Style. Gridviz - Mosaic Style is an interactive map which visualizes European population data in the style of a Roman mosaic. 

For clarity I must point out that this interactive map does not show population density in Europe as it was during the Roman Empire. This is actually a map of the current population density of Europe visualized in the style of a Roman mosaic floor - using data from the European Commission. 

On this map individual tiles are colored to show the number of people living in that area. As you zoom out on the map the tiles represent ever larger equal areas of Europe. Gridvis - Mosaic Style is an interesting way to visualize population density in Europe. I also can't help thinking that the map could be of great use to any map fanatics who are thinking of redecorating their bathrooms. 

You can view a more traditional map of European population density on the EU Population 2011 by 1km Grid interactive map. On this map Dan Cookson has visualized the population of the European Union at the 1km square level. 

The EU Population 2011 by 1km Grid visualizes the number of people living in each square kilometer of the whole EU. You can hover over individual 1km squares on the map to view the total number of people living in that square. If you zoom in on individual cities the map reveals the most densely populated areas and also the outlying satellite commuting towns and suburbs.

You might also be interested in this 3D Global Human Settlement visualization of European population density. This map provides a 3D view of Europe's most densely populated areas as population mountains. 

If you want to view population density across the whole world then I recommend 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 there.