Saturday, August 17, 2019

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.

Friday, August 16, 2019

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.

Thursday, August 15, 2019

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.

Wednesday, August 14, 2019

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.

Tuesday, August 13, 2019

Two Degrees Warmer

In 2015 countries from around the world signed the Paris Agreement, an agreement to try to keep global warming below 2 degrees Celsius by the year 2100. In 2019 many locations across the United States have already surpassed 2 degrees of warming. Two years ago President Trump announced that the United States will withdraw from the Paris Agreement.

The Washington Post has today released a detailed examination of where climate change is having the most visible effects in the United States. In 2°C: Beyond the Limit - Extreme climate change has arrived in America the Post uses historical temperature data from the National Oceanic and Atmospheric Administration temperature to map where temperatures in the U.S. have already exceeded two degrees Centigrade.

According to the Post's analysis seventy-one counties have already experienced global heating of 2-degree Celsius. The Post's story includes a more detailed look at some of the regions of America which are experiencing extreme global warming and the effect that this warming is having on local environments. In particular the Post's story concentrates on the North East, where extreme warming has led to rising seas, loss of land, warmer winters and many other environmental problems.

Animated Wind Maps

Animated wind maps have become very popular over the last few years. Earth: and Windy are just two examples of interactive maps which use weather data from the Global Forecast System to create real-time animated maps of global wind conditions.

US Wind Patterns is another interesting example of an animated wind map. However US Wind Patterns uses historical weather data to visualize the last 72 hours of wind activity in the United States. The map shows the wind direction, speed and temperature measurements from 1200 weather stations on top of an interactive map. Press play and you can watch the changing strength and direction of the wind over the last three days as the map animates through the wind data hour by hour.

US Wind Patterns was made with PhiloGL, a WebGL library for creating data visualizations. The library's demo page includes a number of other map visualizations, including this interesting 3D globe of World Temperature Changes 1880-2011.

Where's the Sun?

Under the Sun is an animated map which shows the daily journey of the Sun as the Earth rotates around its own axis. The map shows the exact point on Earth right now where the sun is at its Zenith. The map updates in real-time. So as you watch the map the sun slowly travels westwards across the land or sea.

Under the Sun also includes information on the current time and the latitude and longitude of the current map view. That's it. Under the Sun is a very simple map but it can show some beautiful aerial views of the Earth and watching the slowly shifting landscape under the sun can be very calming.

You can see where on Earth it is currently daytime and where it is nighttime on the Night and Day on Earth interactive map. This map uses a simple map overlay to show where there is currently daylight around the globe and where the world is in darkness.

Night and Day on Earth uses the Leaflet.Terminator plug-in for Leaflet.js. If you need to show where it is currently night and day around the world then you can use the plug-in to add a night and day layer to your own Leaflet maps.