Friday, May 25, 2018

Viewing Real-Time Satellite Imagery


You can now view and download near real-time full-resolution satellite imagery from NOAA's National Environmental Satellite, Data, and Information Service. At NOAA's Imagery & Data website you can view a number of interactive maps which provide you with access to satellite imagery of Earth taken in the last 24 hours.

The Western Hemisphere map allows you to view the latest 24 hour satellite imagery of the Western Hemisphere, while the Global Archive map allows you to view satellite imagery of the whole Earth. Both these maps include a timeline feature which allows you to see the latest satellite imagery animated on top of an interactive map.

As well as these two maps which allow you to view and download NOAA's latest satellite imagery, the Imagery & Data website includes NOAA's Image of the Day. This feature provides a close-up view of some of the latest significant weather and environmental events taking place around the world. The website also provides a link to NOAA's Historic Events, which looks at satellite imagery of historic storms, floods, fires, and other global events.

The Virtual Globes Museum


The Virtual Globes Museum is a website which allows you to view historical vintage globes as interactive virtual WebGL 3d globes. The collection includes Earth and celestial globes dating back to 1507.

The first globe in the collection is the 1507 Waldseemüller globe. This was the first globe known to include the word 'America'. The label 'America' is placed on what we now call South America. The collection also includes a number of Earth and celestial globes by the Dutch cartographer Willem Blaeu and by the Venetian Vincenzo Coronelli.


The University of Lausanne in Switzerland has released two interactive 3d globes which are digitized versions of the University's globes made by Gerard Mercator in the 16th century. The two recently discovered globes exist as a homogeneous pair, one being a terrestrial globe and the other a celestial globe.

The University has used Esri's Scene Viewer to create their two interactive 3d globes from Mercator's originals. This allows you to inspect Mercator's Earth Globe and Mercator's Celestial Globe in detail from your own browser. The Earth globe is made from plates engraved by Mercator in Louvain in 1541.

Mercator's Earth globe improves significantly on the Ptolemaic view of the world which dominated during the 16th century. For example, his representation of the Mediterranean and Africa are much more accurate than many other contemporary maps based on Ptolemy.


The State Library of New South Wales has also created a couple of interactive 3d globes from vintage historical maps and globe gores. Their Meridian application allows you to view virtual globes of Miranda's World Map (1706) and Coronelli's Terrestial Globe.

Meridian was created using the Three.js library. You can read more about how Meridian created their virtual globes from Miranda's two dimensional vintage map and from Coronelli's globe gores on the DX Lab blog.

Thursday, May 24, 2018

The Spy Planes Spying on Texas


Last year Buzzfeed released an award winning investigation into the use of spy planes by the FBI and the DHS over mainland America. Buzzfeed's Spies in the Skies investigation mapped out the flight paths of the FBI and the DHS planes to reveal the areas where these federal planes have been spying.

The Texas Observer has now released a very similar investigation into the aerial surveillance carried out by the Texas Department of Public Safety (DPS). The Texas Department of Public Safety owns two high altitude spy planes.

In Eyes Above Texas the Texas Observer has used tracking data for the two planes, obtained from Flightradar24, to create a map of where the planes have flown. The Esri map shows all the known flight paths undertaken by both planes from January 1, 2015 to July 31, 2017. The map includes a closer view of all the places where the two planes might have flown into Mexico. Under the Department of Public Safety's own rules the planes are not allowed to fly over other countries.

The Observer has used DPS flight logs to color code the planes' flight paths to show those where the flight's purpose is for border security and those where the flights have another purpose. The Observer's map also includes a search facility. You can therefore enter your own address to see how often the DPS spy planes have flown over your house.

Spy Satellites Spy Shrinking Rain Forest


North Carolina State University has used historical aerial imagery captured by the Corona spy satellite in the 1960's & 1970's to track the loss of the Atlantic Forest. The Atlantic Forest is a rainforest located in the border area between Argentina, Brazil, and Paraguay. Over 85% of the Atlantic Forest has now been lost to deforestation.

The Making of a Forest is an Esri story map which uses three different sources to visualize how the rainforest has shrunk over the last seventy years. As well as using historical imagery from the Corona satellite the North Carolina State University analyzed historical aerial photography captured by the Brazilian government in the 1950's & 1980's and Landsat satellite imagery dating back to the 1970's.

As you progress through The Making of a Forest you can view the fixed-wing imagery and satellite imagery from different decades overlaid on top of a map of the Atlantic Forest. This imagery shows how the parts of the rainforest which are now inside the Brazilian and Argentinian national parks in the area are very healthy. Outside of the national parks what was once the Atlantic Forest is now mainly farmland.

China's Great Sea Grab

For a number of years the Republic of China has been engaged in a huge territory grab in the South China Sea. It has claimed countless coral reefs and engaged in building artificial islands, both of which it is using to construct new military bases. Other countries in the area dispute China's ownership of these islands and are becoming increasingly worried about the country's growing military presence.

Reuters has been examining satellite imagery to track China's military expansion in the South China Sea. In Concrete and Coral Reuters has worked with Earthrise Media to explore China's construction projects, particularly on the Paracel and Spratly islands. As part of this investigation Reuters has mapped out the extent of China's dredging and reclamation work on both island chains. This is presented in two maps showing the extent of the Paracel and Spratley islands before and after China's reclamation work.



Both these maps show that the territory owned by China has increased dramatically over the last few years as it reclaims land for military installations. During the same period the amount of reefs and islands owned by other countries on the Spratly Islands has remained largely the same. Only South Vietnam appears to have reclaimed a little land, and nowhere near to the extent of China.

Reuters' small multiples graphic of the Spratly and Paracel Islands is supported by satellite imagery which similarly shows the extent of China's dredging and reclamation work. The satellite imagery also reveals the extent of China's military construction work on the islands.

The Asia Maritime Transparency Initiative has mapped out all the territorial claims of the Asia Pacific. Its Maritime Claims of the Asia Pacific attempts to provide an as complete, accurate and up-to-date map as possible of all the competing maritime claims in the region.


On the map each country's territorial claims are shown using color-coded borders. The map includes a filter option which allows you to view any combination of countries' claims on the map. By selecting any two country's territorial claims on the map it is possible to see exactly where they have territorial disputes.

The Asia Maritime Transparency Initiative map doesn't show territorial claims for the Spratly and Paracel Islands "due to a lack of clarity about what each country claims".


In the last few years both China and Japan have escalated their military presence in the South and East China Seas. China has also become caught up in diplomatic rows with Vietnam, Taiwan, Malaysia, the Philippines and Brunei over long standing conflicting claims over territorial rights in the China seas.

Al Jeezera has published a map examining the history of the South China Sea Disputes. The map explores some of the historical hot-spots between China and its neighbors in the area since 1974. The map itself was created using Leaflet.js and the Knight Lab Story Maps library.

The Story Maps template means that you can explore the map chronologically, using the forward and back arrows to progress through Al Jaeera's mapped history of the region. You can also click on the map markers to jump to individual locations on the map to learn more about the history of territorial disputes in that area.

Wednesday, May 23, 2018

Travel Time Quantiles


Route Times uses data from Google Maps driving directions to visualize where you can drive to in a set amount of time from the center of five major cities around the globe.

Select one of the five cities on Route Times and a number of polylines will be drawn on top of a Leaflet.js map of the chosen city. Each polyline represents a driving route from the center of the city. Each route is colored to show how long it takes to drive. If you click a route's polyline on the map you can view exactly how long it takes to drive and the distance of the route.

The author of the map, Cris Moya, has released the code on GitHub for a very similar map. GoogleTravelTime can create similar route times maps for any location on Earth, and for any time of day or day of the week (again based on Google Maps's driving directions).

Urbanization in England & Wales


The Urban Growth Explorer visualizes the huge urbanization of England & Wales in the last 150 years. The map overlays modern UK town and city boundaries on top of an 1885 Ordnance Survey map to visualize how Britain's towns and cities have grown since the mid-19th century.

Before industrialization England & Wales were both largely rural countries. In 1801 the proportion of the population living in towns and cities with more than 20,000 people was 17%. In 1891 that proportion had risen to 54%. This shift from a largely rural population to an urban population led to the huge growth in the size of towns and cities. For example, in 1717 the city of Manchester had a population of 10,000. By 1911 it had grown to 2.3 million.

Using the Urban Growth Explorer you can search for a town or city in England & Wales and view (where available) a 2015 town boundary overlaid on top of a map of the location from 1885. If no modern boundary is available for your town you can switch to the side-by-side view to compare the 1885 map with the modern aerial view of your town.


You can also explore the UK's shift from a predominately rural to urban country in Populations Past. In the second half of the 19th Century Great Britain went through a process of demographic transition as the industrial revolution fundamentally changed the way that people lived.

The University of Cambridge's Populations Past is an interactive atlas of Victorian and Edwardian England & Wales. The map allows you to explore some of the huge social and geographical changes which took place in England & Wales during the second half of the 19th century and the effect that those changes had on the population.

The map includes a number of different demographic measures and socio-economic indicators which allow you to explore for yourself the effect of the demographic transition over time and between different locations. The side-by-side view uses two different maps to help visualize the effects of the demographic transition on locations throughout England & Wales over time.

Tuesday, May 22, 2018

The 50 Most Dangerous Cities in the World


The Most Dangerous Cities in the World interactive map shows the 50 cities across the globe with the highest homicide rates in 2017. According to the map the most dangerous city in the world is Los Cabos in Mexico. Caracas is the city with the second highest homicide rate and Acapulco is third.

One of the most obvious observations to make is that all but 3 of the 50 most dangerous cities are in the continents of North America and South America. The 3 not in the Americas are all in South Africa. The 4 U.S. cities in the top 50 are St Louis, Baltimore, New Orleans and Detroit.

When browsing the map you need to click on the 'i' in the map toolbar to make the map markers interactive. Once you've clicked on the 'i' you can select the map markers to view the number of homicides in a city and its homicide rate. If you zoom in on a marker a map label will appear showing where it ranks in the top 50 most dangerous cities.

You can read more about where the data comes from and how the homicide rates are compiled on the gvSIG blog.


If you are worried about traveling abroad then International SOS provide a very basic interactive map of the travel risks for every country of the world. Their Travel Risk Map provides an overview of the travel risks in each country for medical, security and road safety.

Countries are colored on the Travel Risk Map to show the International SOS assessment of the travel risks in these three categories. The map therefore provides a very basic guide as to where it is safe to travel in the world. You should also check your government's latest travel advice as well. Many governments provide useful advice for their citizens planning to travel abroad. For example the UK's Foreign and Commonwealth Office provides up-to-date Foreign Travel Advice.

Mapping the History of the World


MappiMundi is a new interactive mapping platform for recording and exploring historical events in space and time. The ultimate goal of MappiMunid is to create a complete world atlas of historical events one event at a time.

Anybody can become a registered user of MappiMundi and use the platform to map out an historical event. Unregistered users can explore the interactive maps of historical events that have already been created by registered users.

A good place to start exploring the capabilities and available features of MappiMundi is the Atlas of World Territories and Battles throughout History. This project maps out major wars and territories in world history. You can use the timeline (directly under the map) to select specific dates in world history and the map automatically updates to show you country borders at the selected time and major battles that occurred in that date range. You can then click on the country / territory polygons or the battle markers to learn more about the countries or historical events.

There are a number of other interactive history mapping projects working on similar platforms. You can view some examples of these on this post on The History of the World - Part Three.

The New York Subway Rental Map


The NYC Subway Rental Map reveals the median rent for a one bedroom apartment in the area around every stop on the New York subway system. The map can also show you if rental rates have gone up or down at each subway stop year-on-year.

The map provides an interesting visualization of New York's affordable and non-affordable neighborhoods using a map of the city that most New Yorkers are familiar with. Every single subway stop on RentHop's interactive map is colored to show the median rent within 0.6 mile of the MTA subway station. If you select a station's marker on the map you can view the exact median rent in the area and the percentage change to the cost of renting in the area since 2017.

According to RentHop rents have dropped around many stops in Manhattan Island and Brooklyn. In fact about half of the stops in Manhattan experienced drops in the cost of renting. On the other hand many stops in the Bronx have experienced a growth in rental rates year-on-year.