Monday, August 20, 2018

Germany's Plans to Invade Britain


Germany's invasion map of Newcastle - Library of Congress

The German plan for invading Britain in World War II was code-named Operation Sea Lion. Although both Germany and Britain believed that an invasion was unlikely to succeed it didn't stop both sides from planning for a German invasion of Britain. In Germany the Oberkommando der Wehrmacht (Nazi German Supreme Command of the Armed Forces) ordered that a series of military and geographical assessments be carried out in preparation for an invasion of Britain.

These assessments consisted of photographs, drawings and maps of British towns and military & strategic targets. In order to prepare troops for the invasion of Britain a series of maps of the country were drawn up, identifying strategic locations, and military targets. Published in 11 A4 sized folders these invasion plans included 144 maps of British towns and cities and over 1,500 photographs of key military targets.

The maps and photos in these invasion plans highlighted locations which would be important for troop movements, such as airports, railways, docks and bridges. They included strategically important sites, like hospitals, airfields and radio stations. They also identified important infrastructure and industrial sites, for example waterworks and power plants.


The German invasion plans also included photographs of key strategic targets in each town. 
Neue Strassenbrucke uber den Tyne in Newcastle upon Tyne - Library of Congress

The David Rumsey Historical Map Collection has interactive copies of the German invasion maps of Britain. These include both the maps and the photographs identifying Germany's military and strategic targets for the invasion. If you want to find the German invasion map of your town then expand the 'where' section in the sidebar to view an alphabetized list of links to the town maps.

The invasion maps were copies of Ordnance Survey maps on which the strategic and military targets were highlighted. A simple color-code was used when highlighting these targets. For example, bridges are highlighted in black. Railway and goods yards are highlighted in red. Purple is used to show industrial sites, such as waterworks and power plants.

As the German maps were merely copies of Ordnance Survey maps they would presumably not show many of the country's secret locations. Secret and classified buildings like military locations and barracks were often omitted from Ordnance Survey maps at the direction of the British government. This is presumably why during the cold war the Russian's created their own maps.

During the cold war the Soviet Union created detailed maps for thousands of cities around the world. We don't know exactly how the Russian military completed their detailed maps of the west. Presumably they also used freely available maps as the basis for their maps. However the Russian maps often contain military sites left off of western maps (for military secrecy), therefore they must have been based to some extent on knowledge gained from spying and espionage.

John Davies has written an interesting article on the Soviet military maps for the British Library. Soviet Military Mapping of the Cold War Era includes more information about the composition of the Soviet military maps, the cities mapped and more informed speculation on how the maps were made.

Saturday, August 18, 2018

The Ethnic Dot Map of Estonia


The Ethnic Dot Map of Estonia is an interactive map which shows where different ethnic groups are living in Estonia. The map contains 1.29 million dots, each dot representing a different Estonian. The map was created using data from the 2011 census. On the map the blue dots show Estonians, the red dots represent Russians and the green dots are for other ethnic groups. Purple dots show people of an unknown ethnic background.

The map does not show where individual people live. The number of people in each ethnic group is randomly placed in buildings in each census area. This gives an approximation of the numbers of the different ethnic groups in each census block not the geographical distribution of ethnic groups within census areas. The buildings are also not necessarily residential. Therefore it may appear as if people are living in your local schools, hospitals or factories.

Although the map doesn't reveal the geographical distribution of Estonian or Russian ethnic groups within individual census blocks it does provide an overview of their distribution at the town or city level. If you zoom out on the map you can clearly identify neighborhoods and areas where Russian immigrants live in large numbers.

Other Dot Maps

Friday, August 17, 2018

The Streetcars of San Francisco


The wonderful Where the Streetcars Used to Go now includes an interactive map of the historical streetcar network in the East Bay. Where the Streetcars Used to go is a fascinating map visualizing the San Francisco streetcar transit network as it existed in 1941 & 1956 and as it exists today. It now includes the tram lines that were once operated by the Key System company in Berkeley and Oakland.

If you like streetcars then it is a bit depressing switching between the Oakland streetcar network maps of 1941 and 2020. However you can cheer yourself up a little by browsing through the vintage photos of the old streetcars of San Francisco and the East Bay. You can actually filter these wonderful photos of San Francisco's historical streetcars by the different streetcar routes. If you click on a streetcar route on the map the photos, running along the bottom of the map, are filtered to only show photos taken along the chosen line. The name of the selected route is also displayed on the map alongside the dates when the route was operational.


You can cheer yourself up even further by exploring the BC Electric Railway Map. This beautiful looking visualization maps how Vancouver's BC Electric Railway Company transit network looked in the early Twentieth Century. The map plots the historical interurban and streetcar lines of the network between 1890 to 1958.

The map also contains a few photos and Street Views of modern day Vancouver showing how some of the company's historical buildings and lines look today. To view this content click on the 'Introduction' button and then on the markers that appear on the map.

The Cartography Playground



The Cartography Playground is a new interactive website where you can learn about many different aspects of map design, principles and cartographic algorithms. At the moment the Cartography Playground includes components on Map Design, the Douglas-Peucker Algorithm, Contour Lines to Profile, Clustering Methods and Cartographic Generalization. It also includes a quiz where you can test how much you have learned by completing the other five sections.

Each section of the Cartography Playground provides a simple introduction to a different element of cartography. These explanations are accompanied by examples and illustrations. Each section also includes links to further reading on the covered topic.

Cartography Playground includes a number of interactive exercises designed to illustrate, reinforce or test the mapping principles explained in each section. For example, the Map Design section includes an interactive which allows you to change the colors of different map features. While the Cartographic Generalization section includes an interactive map which changes to illustrate the different methods of generalization that cartographers use when making maps.

When you have finished every section of the Cartography Playground you can test how much you have learnt by completing the Cartography Playground Quiz. This multiple-choice quiz tests you on the different aspects of cartography you have explored in the previous five sections.



If you are interested in good map design then you should also bookmark ColorBrewer. Cynthia Brewer's ColorBrewer is an online tool to help cartographers choose good color schemes for their maps. The tool helps you to think about the type of data you are visualizing and the appropriate color scheme to use for visualizing that data.

The tool includes three types of color scheme, sequential, diverging and qualitative. You simply need to choose which scheme best fits your data, choose the number of classes in your data and then choose a multi-hue or single color palette range. As you make your design decisions you can automatically see the scheme being applied to a sample map.

When making your choice of color scheme it is worth reading the advice provided (using the information button) about when to use a sequential, diverging or qualitative color scheme with your data.

Carto has also provided a short explanation of when to used sequential, diverging, or qualitative data. color schemes. It has also provided a number of color schemes to use with each. You can view the palettes for Carto's sequential color schemes, diverging color schemes and qualitative color schemes at CartoColors.

Mapping Raptor Persecution


Birds of prey in the UK all share a common enemy - the human race. Every week the RSPB receive reports of raptors being shot, trapped or poisoned. Many other incidents go unreported. This is why the RSPB has decided to release a centralized hub to monitor and track raptor persecution in the UK.

The Raptor Persecution Hub provides an overview of the illegal treatment of birds of prey in the UK. The hub consists of an interactive map of historical data on raptor persecution going back to 2012. An interactive map visualizes the attacks geographically. The map can be filtered to show the incidents of raptor persecution by date, incident type, county and country.

The Raptor Persecution Hub includes a heat-map view of attacks on birds of prey. If you switch to the heat-map view (using the buttons under the map) you can clearly see where most attacks have been reported. The locations with the most raptor incidents are shown in black and red. This heat-map view shows that upland areas in North Yorkshire, the Scottish borders and Aberdeenshire are hot-spots for attacks on birds of prey. The RSPB believe that this is direct result of the persecution of birds of prey on land managed for grouse shooting.

Thursday, August 16, 2018

Mapping the Homeless of LA


In January 2015 the Los Angeles Homeless Services Authority carried out a survey of the homeless in Los Angeles County. The survey estimated that there were 44,359 homeless living in the county. Using the data from the count the Los Angeles Times created a dot map to visualize the distribution of homeless people throughout the county.

Each dot on the Where are L.A. County’s Homeless? map represents one homeless person or a makeshift shelter or vehicle occupied by the homeless. The dots do not represent the exact location of homeless people recorded in the survey but were randomized throughout each census tract. If you select a census tract on the map you can view a breakdown of the number of homeless counted in the neighborhood at the end of 2014.


In the latest point-in-time count, carried out in 2017, there were more than 57,000 men, women, and children estimated homeless in Los Angeles County. Esri has used the data from the count and other publicly available data to explore how GIS can be used to combat homelessness in the county.

In Combating Homelessness in Los Angeles County Esri has created a number of mapped visualizations which show the distribution and characteristics of the homeless population in L.A. County. The story map continues by showing how GIS can be used to identify priority areas to target resources for the homeless.

The Combating Homelessness map makes a lot of use of the L.A. point-in-time count. These counts are required by the US Department of Housing and Urban Development and are conducted every one or two years across the US. You can use Esri's story map as a template for creating a map visualizing the homeless problem in your own area and to identify priority locations to target resources.

Making Vintage Panoramic Maps


The Buffalo News has created a nice interactive map from an 1880 panoramic map of Buffalo, created by E.H. Hutchinson. The Buffalo News interactive version of the map allows you to zoom-in and explore this vintage oblique view of the city in close detail.

The map includes a number of map markers which provide information about some of the landmarks shown on the map and some historical photos of the same landmarks. Each of these information windows also includes a link to a Buffalo News article on the selected location, from the newspaper's weekly series on how the city has changed over the last 138 years.

From 1880 to Today is a Leaflet.js version of a panoramic map from the Library of Congress collection. The Library of Congress owns over 1,500 vintage panoramic maps of towns and cities across the United States. You can create your own interactive map from any of these Library of Congress panoramic maps using the IIIF manifest provided for each map and the Leaflet-IIIF plug-in for Leaflet.js.


Leaflet-IIIF is a simple to use plug-in for creating a Leaflet based browser for IIIF manifests or images shared using the IIIF Image API. Using this plug-in you can make interactive maps from tens of thousands of manuscripts, paintings and other images held by some of the best known global art galleries, museums and universities. And the Library of Congress.

I used the Leaflet-IIIF plug-in to create a Leaflet.js map of another vintage panoramic map from the Library of Congress. This Sherbrooke Panoramic Map shows a 1881 panoramic map of the southern Quebec city. I worked out the latitude and longitude of individual buildings on the map by using the Leaflet-Hash plug-in to create a dynamic URL for the map with the latitude and longitude shown in the URL for what ever is at the center of the map.


You can also create a simple interactive map from any of the Library of Congress vintage panoramic maps using the antirubbersheeter tool. Antirubbersheeter is a new web service which can help you create a Leaflet.js map of any image, with its own co-ordinate system. The problem with using an IIIF manifest as your background map is that you then need to work out how to geocode points on your map if you want to add markers. Antirubbersheeter does all this for you by creating a unique co-ordinate system for your uploaded image.

This means that you can easily use Leaflet.js to make interactive maps from vintage maps, fantasy maps, game world maps or from any image that you want to use. It is really easy to use Antirubbersheeter. Just upload your image. Add a list of places you want to geocode on your image. Antirubbersheeter then allows you to simply click on your image to geocode the list of places where you want to add markers.

When you've finished added locations to your image Antirubbersheeter outputs the JSON of your geocoded locations, providing you with the co-ordinates for each of the places you want to mark on your very own Leaflet.js map.

Antirubbersheeter includes a demo map which you can view to see how this all works in practice. I've also created a slightly simpler demo map which you might find a little easier to work from.

Wednesday, August 15, 2018

The Key Seats in the Midterm Elections


The New York Times has mapped 62 key House seats which could go either way in this year's midterm elections. The Democratic Party must win at least 23 Republican held seats to win the House in November. To take control of the House the Democratic Party or the Republican Party must reach the 218 seats needed for a House majority

In Tracking the House Races to Watch in the 2018 Midterm Elections the NYT has mapped out the 62 key House seats which could win the House for either party. These are the seats which according to the Cook Political Report are likely to be the closest races. The seats are colored on the map by who is likely to win the seat based on the latest analysis from the Cook Political Report. The yellow seats are the seat which are currently the hardest to call. The red and blue colored seats are the competitive seats which could be won by either the Republican Party or Democratic Party respectively (based on the analysis of the Cook Political Report).

According to the Cook Report the Democratic Party has a total of 192 solid and likely to win seats. The Republican Party currently has 205 solid and likely to win seats. It says that there are 38 seats where either party has a good chance of winning.

Exploring Stonehenge's Prehistoric Neighbors


Stonehenge is one of the most iconic prehistoric monuments in the world. Every year it is visited by over 1.5 million people. I wonder how many of those visitors visit any of the other 300 odd Neolithic and Bronze Age barrows that are within walking distance of Stonehenge.

One way to appreciate the astonishing prehistoric landscape around Stonehenge is by exploring the Stonehenge Barrow Map. This Google Map shows the location of prehistoric barrows in the vicinity of Stonehenge. While it might not be the same as visiting the barrows in person the Google Maps aerial view does give a unique perspective on these prehistoric sites and reveals some features that aren't always apparent on the ground.

The barrow markers on the map are color-coded by how they are grouped by Richard Colt Hoare in his 'The Ancient History of Wiltshire'. The map also has a search facility which allows you to search for barrows by name and by other criteria, such as what artifacts were found in them. You can find out more about individual barrows by clicking on its marker on the map. This will open an information window containing descriptions from 19th-century and modern-day researchers. It also includes links to relevant research & websites and to photographs of the artifacts discovered in the selected barrow.


Historic England's 2002 National Mapping Project of Stonehenge added another 539 important archaeological sites around Stonehenge. About thirty percent of the newly discovered sites were prehistoric or Roman in date. These included ring ditches, field systems, round barrows and enclosures of various forms dating from prehistory.

You can now explore and download research reports from the Stonehenge NMP for 46 of the most important new historic sites discovered around Stonehenge, The Stonehenge World Heritage Site Landscape Map allows you to view aerial imagery of these 46 NMP listed sites, learn more about each site and download each site's report.

All 46 sites can be navigated to from the map sidebar or by clicking on the numbered markers on the map. When you select a site from the sidebar or map, the map zooms to show the listed site and information for the site is displayed in the map side panel. A link to download the individual site's NMP report is also provided in the map side panel.

Tuesday, August 14, 2018

Saving Half the Planet


The biologist Edward O. Wilson argues that if we conserve half the Earth’s land & sea we will be able to save most of the planet's biodiversity from extinction. His proposal is a simple to understand concept which, if implemented, could save life on planet Earth. The Half-Earth Project was born out of Wilson's proposal to ensure that Earth's biodiversity is saved by protecting half all the planet's land and sea.

In order to better understand how to protect life on our planet the Half-Earth Project has begun to map out the rich biodiversity of life across the globe. They have released an interactive 3D globe which provides a heat-map view of biodiversity across the planet's land. The map provides a guide as to the areas with the richest biodiversity and therefore the areas which are most important to protect from further human development.

You can explore the biodiversity of life on Earth in more detail by scrolling through the map sidebar. This sidebar provides more information about the biodiversity of our planet. It includes a number of highlighted words and phrases which can be selected to view different aspects of biodiversity on the interactive map. It also allows you to view biodiversity richness maps for individual species and the natural areas of the planet that are already protected.