Friday, December 15, 2017

New York's Shrinking Rivers

The Changing Shoreline of New York City uses historical maps, from the New York Public Library’s collection, to explore how Manhattan has physically grown in size during its brief history. This fascinating look at the changing landscape of New York was created by Laura Blaszczak during her internship at the New York Public Library.

As you scroll through this impressive story map historical maps are used to show how Manhattan's many rivers, creeks, brooks and bays have been managed or even built over. These historical maps are overlaid on top of a modern map of New York. Each has an opacity control that allows you to directly compare the historical with the modern map of the city to illustrate how Manhattan's landscape has changed.

BTW - I really like the button (which appears on this map when you view it on a mobile device) that allows you to switch the browser's focus between the map and the scrolling content. This appears to have been achieved by adding and removing the user's ability to pan the map by creating a simple toggle map panning function.

The History of Data Visualization

The magnificent David Rumsey Collection has a new 'data visualization' subject field which allows you to search and explore some wonderful examples of early data visualizations. It features data visualizations by pioneers of information graphics, such as Charles Minard, Henry Beck and John  B.Sparks.

One of my personal favorites in this data visualization collection is Levi W. Yaggy's Geographical Definitions Illustrated. This vividly colorful educational chart was designed to be displayed in a classroom. The chart depicts examples of a wide range of geographical features, such as deltas, estuaries and harbors.

Charles Minard was a pioneer of the use of graphics in engineering and statistics. His most famous visualization was his flow-map of Napoleon's disastrous Russian campaign. Minard's flow-map of Napoleon's 1812 Russian campaign isn't in the David Rumsey collection but the collection does have Minard flow-maps showing global emigration in 1858, the Atlantic trade in wool and cotton and the movements of mineral fuels on railways and waterways.

In each of these maps scaled arrows are used to show the direction and scale of the movement of goods and/or people.

John B. Sparks' Histomap of Evolution is a logarithmic timeline which visualizes ten thousand million years of evolution. The chart was an accompaniment to John B. Sparks equally ambitious Histomap, which condensed 4000 years of human activity into one chart. The Histomap was 5 feet long and was sold in 1931, by Rand McNally, for $1.

This history of the world starts at the top of the Histomap in 2000 BC and progresses forward in time as you travel down the chart. The width of the various 'states, nations and empires' equates to their 'relative power' through history.

These are just a few examples which I found while browsing the David Rumsey Collection. If you are interested in data visualizations, information graphics or design then you will enjoy browsing the 'data visualization' subject field for yourself. I haven't even got around to discussing Henry Beck's early London Underground maps or Charles Booth's map of London poverty.

You might have noticed that all of these examples from the David Rumsey Collection are displayed using the LUNA viewer. In other words IIIF has been used to display each of these data visualizations. This means that you can display any of these visualizations yourself in a Leaflet map using the Leaflet-IIIF plug-in. If you are interested in mapping any of these examples with Leaflet then you need to click on the 'share' link on its visualization page on the David Rumsey Collection. You can then click on the IIIF link to grab the URL for the IIIF manifest.

Thursday, December 14, 2017

The MP's Expenses Map

Members of Parliament representing the Scottish National Party tend to claim more in expenses than MP's from other political parties. 8 out of the top 10 biggest expenses claims made by Members of Parliament last year were by MP's from the SNP. The SNP would probably be keen to point out that their MP's have the furthest to travel from their constituencies to Westminster and therefore have the highest travel costs.

Voters can access information about their Member of Parliament's expenses on IPSA's Interactive Map. The map is colored to show which political party holds each UK constituency. The map can also be used to view the expenses of each Member of Parliament for every year since 2010. If you click on a constituency on the map you can view the name of the local MP (under the map). If you then click on the MP's name you can view their expenses for each year. The expense for each year are broken down to show how much they have claimed for office costs, accommodation, staffing, travel and other costs.

The UK's Independent Parliamentary Standards Authority (IPSA) was established in response to the parliamentary expenses scandal. In 2009 a series of revelations were published about extortionate expenses claims made by a large number of Members of Parliament over the previous years. IPSA is now responsible for monitoring MP's expenses and for paying their salaries & expenses.

Interactive Map of the Southern Sky

The Australian National University has released the most detailed interactive map of the southern sky. The Southern Sky Viewer allows you to explore nearly 300 million stars and galaxies that can be seen from the southern hemisphere.

The map is made from images captured by a specially-built, wide-field survey telescope at Siding Spring Observatory near Coonabarabran. The basemap is made up of 70,000 ultra-high-resolution images, which means that you can zoom-in on the map to examine stars, nebula and galaxies in close detail.

The map doesn't appear to include an option to link to specific views on the map. However the map does include a search option which allows you to search for features by name or by position. Try searching for these:

Centaurus A
Horsehead Nebula
Carina Nebula
Alpha Carinae
Helix Nebula

Wednesday, December 13, 2017

Dreaming of a White Christmas

One of NOAA's most popular interactive maps is the First Snow Map, which provides a nationwide guide to when you can expect the first snow of the winter. The map shows the date at your location when the chance of snow is at least 50%, based on historical weather records. NOAA have also created a similar looking map which shows the historical predictability of whether you can expect a white Christmas.

The Are you dreaming of a white Christmas? map uses historical weather data to provide a prediction of the chance of experiencing at least 1 inch of snow at your location on Christmas Day. The whiter the map at your location then the more chance you have of having a white Christmas. The chances of you experiencing a white Christmas are based on the last three decades of weather records at your location.

150 Years of Mountain Photography

Between 1861 and 1958 land surveyors took thousands of photographs of Canadian mountains. These photos provide a wonderful resource of Canada's environmental history. A resource which scientists can use to observe how the environment has changed since the photos were taken.

The Mountain Legacy Project (MLP) has spent the last nine years working out where each of the original land surveyor photos were taken. They have then traveled to each location to capture the exact same views with brand new photographs. By comparing the new photographs with the originals the Mountain Legacy Project can then document how the landscape and environment has changed over the years.

You can examine how Canada's mountains have changed for yourself using the MLP's Explorer. This interactive map allows you to explore the MLP collection of historical photographs by location and directly compare the historical view with the same view today, as depicted in MLP's modern photos.

While exploring the MLP collection of historical and modern photos you can use the Image Analysis Toolkit to directly compare the historical and modern photos of the same view. The Image Analysis Toolkit includes a number of visualization tools for comparing any two photos side-by-side. If you want to spot signs of global warming between the historical and modern views then you might want to look out for glacial change, changes in tree cover (tree lines creeping higher), vegetation change and retreating snowcaps.

36 Years of American Wildfire

The most common cause of wildfires in the United States is lightning. However a large number of wildfires are started by humans, both deliberately and accidentally. You can now explore the causes of wildfires in the USA on a new interactive map.

Jill Hubley has mapped every single American wildfire since 1980. Her interactive map, U.S. Wildfire Causes 1980-2016, visualizes historical wildfire data and even shows which fires were caused by humans and which had natural causes.

The U.S. Wildfire Causes map uses Federal Wildland Fire Occurrence Data from 1980 until 2016. It shows fires started by humans (like accidents or arson) in orange and natural causes in green. No base map is shown under the data when the user is zoomed out on the map. A base map is hardly needed as the wildfire data on its own creates an easily recognizable map of the United States. However a base map is added to the map when you zoom-in, so it is possible to explore the wildfire data by location.

If you click on the 'Specific Cause' button you can view the wildfires colored by the specific natural or human cause. You can also view all the causes of wildfires ranked by the number of acres burned. For most years lightning is the most common cause of wildfire, although in 1980 and 1985 pyromania was the top cause. In most years pyromania and cooking fires appear among the most common causes of wildfires.

Tuesday, December 12, 2017

How Time Can Bend Space

Showing how long it takes to travel between two different points on a map can be difficult. The most common approach is probably to use an isochrone layer, which uses color to visualize journey times geographically.

In the example above, from Mapbox, driving times from a selected point on the map are shown using different colors. In this example there is a continual gradation between the different colors. However in lots of isochrone maps lines are drawn on the map connecting points which can be reached in the same travel time. For example lines might be used to show how far you can travel in 10, 20 & 30 minute increments.

Another approach to visualizing travel time on a map is to use a time cartogram. In a time cartogram geographic distance on the map is replaced by a time attribute such as travel time (Eric Fischer has posted a few time cartograms of San Francisco to Flickr). However the problem with time cartograms (as with all cartograms) is legibility. When you distort a map by some other variable apart from distance the map can quickly become illegible, as users struggle to recognize the geography.

Nate Parrott has created an interactive time cartogram to show NYC Subway Travel Time. If you click on a subway station on Nate's map then the subway map automatically redraws itself so that the distance to all stations is based on the journey time from your selected station. This interactive time cartogram works really well as a visualization of journey times and it doesn't suffer from the usual problems of illegibility common to many time cartograms.

There are a number of reasons why the NYC Subway Travel Time Map works so well. To start with users are already familiar with the concept that transit maps distort geography and are not strictly geographically accurate. Users are also familiar with the use of colored lines to show the transit system's different lines. If you are already familiar with a line and its stations on the New York subway map then you will still be able to pick it out on a distorted time cartogram based on the line's color. Even if the NYC Subway Travel Time map confuses you then you can still mouse-over a station on the map and quickly reorient yourself with the New York subway.

If you want to make your own isochrone travel time maps then you might like this How to Make a Travel Time Map post.

Chicago Energy Consumption

The Chicago Energy Database Map is a multivariate visualization of electricity and gas consumption in Chicago neighborhoods. The map uses both color and height in order to show two different variables. Gas consumption in each neighborhood is shown on the map using color, while the height of the neighborhood reflects the amount of local electricity consumption.

Using 3d towers and color allows the map to show two different variables at the same time. The result is an effective visualization of energy consumption in Chicago, as users can clearly see that both gas & electricity consumption is lower in the city center than in the surrounding neighborhoods.

The Chicago Energy Database Map does have some problems as a multivariate visualization but these problems are largely due its age.The map is a few years old now and appears to have been designed in Leaflet using some trickery to provide the oblique bird's eye view of the city map. The result is that the user can't tilt the map and can only rotate the map in 90 degree stages. This can make it a little difficult to view all of the neighborhoods on the map, as the taller neighborhoods in the foreground can obscure any shorter neighborhoods behind them.

Today the map could be created using a modern vector map library, such as Mapbox GL - which supports pitch & bearing. If the map was recreated in Mapbox GL the user would be able to tilt and rotate the map at will and would be able to explore the data more easily. You can view some examples of 3d towers being used to visualize two or more variables in this post on Mapping Population in 3D. You can view a few other methods of mapping more than one variable in Jim Vallandingham's Multivariate Map Collection.

Monday, December 11, 2017

Guns Across State Lines

New Jersey has some of the most restrictive firearm laws in the country. Unfortunately for New Jersey most of the other 49 states aren't so fussy about selling guns. That might be why 79% of guns in New Jersey recovered and traced by the Bureau of Alcohol, Tobacco, Firearms and Explosives were bought out of state.

Axios has mapped the ATF's Firearms Trace Data - 2016 to show the top ten out of state sources for firearms for each U.S. state. The interactive flow map in How guns move across state lines visualizes the top ten out of state sources for recovered and traced guns in each state. If you hover over a state you can see how many guns were traced by the ATF in that state in 2016. You can also see the percentage which were originally purchased out of state and the ten states where the most guns were originally purchased.

If you want to make your own interactive flow map then you might be interested in Sarah Bellum's Canvas Flowmap Layer for ArcGIS or the Leaflet.Canvas-Flowmap-Layer.