Friday, March 05, 2021

Heritage Under Threat

The National Trust has released a new interactive map which highlights the risk to the UK's most important heritage sites from climate change. The National Trust is a charitable organization responsible for preserving land and buildings of national importance and/or outstanding beauty. The trust's new map identifies the future climate threats, such as coastal erosion, extreme heat and flooding which endanger the UK's most important buildings and cultural heritage sites.

The National Trust Climate Hazards map includes a number of layers which visualize the UK's present (2020) and future (2060) climate threats from extreme heat, storm damage and land erosion. Select one of these layers from the map menu and you can view the threat levels overlaid on top of a map of England, Wales and Northern Ireland (Scotland has its own National Trust organization). 

The small arrow at the bottom of the map opens another menu which allows the user to find and zoom to individual National Trust run properties. You can use this menu to assess the climate risk to individual buildings or land run by the National Trust. If you are interested in visiting a National Trust run heritage site in the UK then you can also view all the trust's buildings and land on the National Trust's Search Places interactive map. This map provides more details on each of the Trust's properties including information on the property's history and opening times.

Thursday, March 04, 2021

The Cold Blob in the Gulf Stream

New climate data shows that the Gulf Stream is now at its weakest in more than 1,000 years. The Gulf Stream is the warm Atlantic ocean current that stretches from the Gulf of Mexico across the Atlantic Ocean to the western coast of Europe. The Gulf Stream has a huge influence on the climates of the east coast of North America and of western Europe. Any weakening of the Gulf Stream could have serious consequences for the climates on both sides of the Atlantic, increasing sea levels on the east coast of America, causing colder weather in the UK, more heatwaves and droughts in western Europe and reduced rainfall in northeast Africa.

The New York Times has published a new interactive story map which explains how the Gulf Stream works, how it influences the climates in North America and western Europe and how its weakening could have serious consequences. In the Atlantic Ocean, Subtle Shifts Hint at Dramatic Dangers is a scrollytelling visualization of the ocean currents which carry the heat of the Caribbean waters up the east coast of the United States and across the Atlantic to Europe.

The NYT's globe goes on to show how a new 'cold blob' in the Atlantic, caused by melting Greenland ice, could seriously weaken the Gulf Stream. The accompanying article in the NYT explains how a previous weakening of the Gulf Stream, thousands of years ago, led to a drop of temperatures in Europe of around 15 degrees Celsius and led to North Africa becoming even more arid than it is today.

Where is the Brave Heart of Scotland?

Alasdair Rae has created an interactive map which shows both the geographical center of Scotland and its 'population weighted' center. 

There are of course a number of different methods that you can use to map the geographical center of Scotland - each of which will result in a different center point for the country. For example in 2002 the Ordnance Survey used a 'centre of gravity' method to determine the exact center of Scotland. The center of gravity method looks for the point at which a cardboard cut-out of Scotland could be perfectly balanced on the tip of a pencil. Using this method the OS determined that the center of Scotland is a point located between Blair Atholl and Dalwhinnie.

Alasdair's Where's the Centre of Scotland? interactive map uses a very similar methodology to the OS. The result is that Alasdair's geographical center point is very close to the one found by the Ordnance Survey, close to the village of Dalwhinnie. In his blog post, similarly entitled Where's the Centre of Scotland, Alasdair discusses some of the different ways that you can attempt to calculate the center of Scotland (or any other country). In this discussion he concentrates largely on the question of how you define 'Scotland' and how this affects where its center will be found. 

Alasdair's map also shows Scotland's 'population weighted' center. This point is based on the population distribution of Scotland. It finds the point in the country which is at the center of where people actually live. The population weighted center of Scotland is a lot further south than its geographical center. This is because around 60% of Scots live in the 'Central Belt' of the country (which can very loosely be defined as the thin belt from Glasgow to Edinburgh).

Wednesday, March 03, 2021

I Am Not a Dot, I Am a Free Man

Last week saw the release of two excellent dot maps, Kenneth Field's Presidential Election 2020 map and NBC's coronavirus deaths map 500,000 Lives Lost. My only problem with these two dot maps is that they both fail to acknowledge that using a dot as a mode of representation is an inherently political act. To paraphrase The Prisoner, 

I am not a dot, I am a free man.

I for one don't want to be represented on a map as a derogatory dot. Surely we can all agree that in these enlightened times people should be not be represented as dots on maps but as real people. 

For example William Davis's Beach Crowd interactive map shows a crowd of people on a Miami Beach not as small dots but as tiny little people. To simulate his crowded beach scene William has used Propublica's Wee People font, which is a typeface which uses people shaped silhouettes, "to make it easy to build web graphics featuring little people instead of dots".


Putting my cartographic wokeness aside for a moment I don't think that Wee People would actually work as a replacement for dots in most actual dot maps. For example Kenneth Field's 2020 American election map uses different colored dots to show Republican and Democratic voters. Readers of the map are able to spot patterns in the vote based on the density of these colored dots. I believe that these patterns would be less legible if voters were represented on the map using Wee People silhouettes instead of dots. The different shaped silhouettes would result in a less legible map.

Which doesn't mean that the Wee People silhouettes shouldn't be used on interactive maps. William's Beach Crowd map shows that the Wee People font is very effective in visualizing crowds. As we emerge from lockdown I suspect that a lot of event planners will be thinking very closely about crowd numbers. Simulating crowd numbers within an event area using Wee People on an interactive map could be very useful for visualizing how many people could safely attend a post-lockdown event.

Tuesday, March 02, 2021

Conjoined Twin Towns

Sãotá is a really interesting experiment which merges the map data of two very different cities to create a map of an imagined conjoined city. The map was created by Near Space Interface and combines geodata from the Brizilian city of São Paulo and the Colombian city of Bogotá. 

The new 3D map of the imagined city of Sãotá combines map data from two neighborhoods in Bogotá (La Candelaria and Chapinero) with data from two neighborhoods in São Paulo (Higienópolis, Paraisópolis). You can explore this new city of  Sãotá as an interactive 3D model. You can rotate around this 3D model and even zoom in on details in the 3D models of the city's buildings. 

The 3D map of the city of Sãotá sits underneath a dynamic animated point cloud, which continually flies overhead. This animated point cloud uses data from air pollution sensors situated in Bogotá and from burned area data from the Amazon. The result is an artistic visual metaphor of the environmental health risks which loom over many South American cities.

Mapping a Landslide

In February more than 200 people were killed in the Himalayas when a landslide on India's second highest peak caused a flash flood which swept away villages and two hydro-electric projects. Such large landslides are rare at this time of year, leading climate scientists to warn of the potential for ever increasing numbers of deadly landslides in the Himalayas as the planet continues to warm.

Detailed satellite imagery can help scientists to more clearly understand the causes and consequences of large landslides. Reuters has used high resolution satellite imagery of Raunthi from before and after the landslide to map the extent of the destruction caused. In Disaster in the Himalayas Reuters has mapped Planet Labs satellite imagery on top of a Digital Elevation Model to map the steep face of Raunthi before and after the devastating landslide. 

In the article Reuters also uses photos and satellite & aerial imagery to document the landslide, the extent of the flash flooding and the damage caused to the local villages, bridges and dams.

Pratik Yadev has also used satellite imagery to provide before and after maps of the Raunthi landslide. His Swipe Between Maps visualization uses Sentinel-2 satellite imagery with Mapbox's 3D terrain view to show Raunthi before and after the February landslide. Two 3D aerial imagery maps are placed side-by-side on Pratik's visualization allowing the user to easily compare the before and after imagery by swiping between the two maps.

The two maps are synchronized together which means that you can explore the before and after imagery in detail by zooming in and rotating the 3D map. As you zoom or pan in one map the other map automatically zooms and pans to stay centered on the same location and view.

Monday, March 01, 2021

Discovering the Northwest Passage

Arctic Fog is a fascinating historical journey into the discovery of the Northwest Passage and the Northeast Passage. The map recounts all the important expeditions carried out by explorers through the ages which eventually lead to the discovery of sea routes from Europe, through the frozen north, to the Pacific and towards Asia.

At the beginning of Arctic Fog you can choose whether you want to discover the Northwest Passage or the Northeast Passage. Choose either of these and you can take an historical journey through all the important and significant expeditions which would lead to the discovery of the chosen passage.Each of these two story maps will take you on a chronological journey through time, exploring in detail all the significant expeditions on the voyage to the discovery of the Northwest and Northeast Passages.

At the beginning of both the Northwest Passage and the Northeast Passage story maps the areas which before their discoveries had been unnaviagable or believed to be impassable are fogged out on the map. As you progress through the timeline the different expeditions reveal new areas of the map. Progress through all the expeditions and the passages are finally revealed on the map.

Switzerland is Now Open

The Swiss Federal Office of Topography, or 'Swisstopo' as they are officially known, is Switzerland's national mapping agency. Swisstopo are renowned for their incredibly detailed and accurate topographical maps. Maps which you can now use in your own mapping projects.

From today Swisstopo is making its geodata free to use according to the principles of Open Government Data (OGD). This means that you can Swisstopo's national maps, orthophotos and geological vector data in your own mapping projects - free of charge. 

To get started you should head over to Swisstopo's new Free Geodata page, which explains in detail which of its products are now freely available and which also includes links to Swisstopo's free geodata and geoservices. If you are interested in creating interactive maps using Swisstopo's map tiles then you might be interested in the JavaScript API examples for Swisstopo's Web Map Tiling Services. This section of Swisstopo's API docs includes links to a number of demo maps showing Swisstopo's map tiles being used with Leaflet.js, OpenLayers 3 and CesiumJS.

Saturday, February 27, 2021

Making History with Maps

Making History Sandbox is an interesting interactive mapping tool which allows you to make maps which show developments over time. It is probably easiest to explain this tool using a working example - so here is a little demo map of an animated timeline I created with Making History Sandbox.

Essentially the tool consists of a timeline and regions which can be colored on the map. To create a history timeline map you add frames to this timeline with different areas colored on the map. By adding additional frames to this timeline you are then able to show geographical developments over time. 

By default the world is mapped to the state level. However Making History Sandbox allows you to import your own region/territory data as a geoJSON file. So, for example, in the United States you could import county boundaries to plot developments over time at a higher resolution than the state level.

It is possible to save and load your created timelines. Unfortunately Making History Sandbox doesn't have a 'share' option so it isn't easy to share your created timeline with anybody else.

Friday, February 26, 2021

The Affordable Housing Map

The average house price for all home types in the United States is now around $295,000. The days of being able to buy a five figure starter home are fast coming to an end. But they aren't over just yet.If you want to know where your can find a home for less than $100,000 then you can refer to Social Explorer's Housing Units Less Than $100,000 interactive map.

Housing Units Less Than $100,000 uses data from the 2015-19 American Community Survey to visualize the density of affordable starter homes in the United States. This choropleth map shows the number of homes valued under $100,000 at the census tract level.If you click on an individual census tract on the map you can view the exact percentage of homes in the tract valued under £100,000.

The map reveals that the lowest density of affordable starter homes are along the east and west coasts. Texas appears to have the highest percentage of homes valued under $100,000. Seven of the ten counties with the highest percentage of five-figure homes are at the edge of the South Plains in Texas. These include King County, where 96.2% of homes are valued under $100,000, Stonewall County (90.2%), and Hardeman County (86.6%).