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.

The American Murder Rate Map


A new interactive map allows you to explore trends in violent crimes in America's biggest cities. The map, created by a team of social scientists at New York University, allows you to view the murder rates in cities across the USA.

At launch American Violence consists of an interactive map visualizing the murder rates in 84 of the largest U.S. cities. Going forward the map will also show neighborhood-level figures on violent crime in the largest U.S. cities (with available data). The murder rates shown on the map will be updated monthly to provide up-to-date information on violent crime. The data is from the F.B.I.'s Uniform Crime Reports, city police departments and other vetted sources.

The initial map view uses scaled map markers to show the last year's murder rate in each of the featured cities. A drop-down menu at the top of the map allows you to view the murder rates for longer periods or to view the murder rate for the last month. Another drop-down menu also allows you to view trends in city murder rates, visualizing which cities have falling or rising rates of homicide.

Monday, August 13, 2018

Fracking in California


California's Getting Fracked is a story map created by Faces of Fracking to illustrate the impacts of fracking in California. The map takes you on a tour through some of the state's most high-intensity fracking sites responsible for some of the most serious environmental and health concerns.

As you scroll through the story the locations of oil & gas wells in the LA Basin are added to a background map. As you continue scrolling the oil & gas well markers on the map are re-scaled to show the number of pounds of toxins that each well has released. California's Getting Fracked also looks at the number of high–intensity production wells across the whole of California. Both the LA Basin and state maps include a layer showing the groundwater aquifer.

You can read more about the methodology used in creating the map and the data sources used on the Faces of Fracking website.

3D Models in Mapbox GL


Andrew Harvey has created an impressive demonstration overlaying a 3D model on top of a Mapbox GL map. His Add a 3D Model to a Mapbox GL JS Map places a 3D model of a radio telescope on top of an interactive map.

Adding a 3D model to a Mapbox GL map allows the user to view the model from lots of different angles. If you right-click on the map you can rotate around the model and adjust the angle of view. While Andrew hasn't done it with his demo, you could also use the Flyto method in Mapbox GL to animate around or zoom in and out on the model on the map.

The 3D model in Andrew's map uses the glTF file format for 3D scenes and models. This is a well used format and there are plenty of freely available glTF files of 3D models on the internet. If you want to experiment with adding other 3D models to Mapbox GL then you are spoiled for choice of ready made 3D objects (for example try Sketchfab).


You can also use glTF 3D models with the Cesium WebGL 3d globe engine. To get started you should check out the Cesium 3D Models tutorial. Or, if you want to jump straight to a working 3D globe with 3D model, have a look at the 3D models sandcastle.

For the 3D models tutorial Cesium created a number of 3D models, including a plane, a milktruck and a hot-air balloon. If you wanted you could try overlaying these on a Mapbox GL interactive map.

The UK's Secret Photogenic Hot-Spots


If you want to increase the number of your followers on Instagram then you could start by posting some stunning photographs of beautiful locations that nobody else has heard of. Luckily for UK photographers the Carphone Warehouse has created an interactive map of some of the UK's most stunning but little known locations. It has identified locations in cities across the country that are both extremely photogenic and under-photographed.

In London the Off the Beaten Snap interactive map ignores well known and over-snapped locations such as Buckingham Palace and Big Ben in favor of locations such as the beautiful Neasden Hindu Temple and the ruins of the church St Dunstan-in-the-East. The map has similar off-beat locations in cities across the UK, where you can capture some beautiful snaps of buildings and places which are unfamiliar to even many of the locals living near-by.


If you are more interested in taking photographs of the most snapped locations around the world then you need Sightsmap. This interactive map provides a fascinating insight into the most photographed locations around the world.

Sightsmap is an interactive map which shows where photographs have been submitted to Panoramio. It provides a heat map based solely on the number of available Panoramio photos for any area. The dark and the blue areas on the map represent areas where fewer photos have been submitted, the red areas show where more photos have been taken and the yellow areas show the most photographed locations.

You can click anywhere on the Sightsmap map to reveal the location and to see an example photo (where available) which has been submitted to Panoramio at that location.

Saturday, August 11, 2018

How Big is the Mendocino Complex Fire?


The Mendocino Complex Fire has now become the largest fire in California's history. This has led to an outbreak of mapped visualizations of the fire. Some of these maps have attempted to visualize the size of the fire and how it compares to previous Californian fires.

The Guardian's report on the fire includes an animated map which shows how the fire has spread since it started on 27 July. How the Mendocino Complex fire became the largest in California history also includes a static map which overlays the area of New York City on top of an aerial view of the fire. The Guardian report on the fire ends with a timeline of Californian fires showing the relative size of each fire.

You can also see how the Mendocino Complex fire compares in size to previous California fires on an interactive map created by Mercury News. Their California’s Biggest Fires article includes a Google My Map which overlays the footprint of California's 10 biggest fires on top of a map of the Bay Area.


The New York Times has also released a visualization of the largest Californian fires. In Three of California’s Biggest Fires Ever Are Burning Right Now the NYT shows the footprints of the 29 largest wildfires in California's history in order of the size of the fires.

Three fires burning right now in California are in the top 28 of the state's largest fires. This small multiples visualization shows this year's fires in red, while the footprints of fires from previous years are shown in yellow. Later in the NYT's story the footprints on the three active fires are also shown on top of a static map of California.


NBC Philadelphia has created an interactive map which actually allows you to compare the size of the fire to any location. The See How Big the Mendocino Complex Fire Would Be in Your City map allows you to view the shape of the fire on top of any city. Use the search function or pan the map to see how the fire compares to your location.

The NBC map was made with the Leaflet.js mapping library. The Turf.js geospatial analysis library was used in order to rescale the fire shape depending on the degree of latitude of the current map view (to compensate for the distortions of the Web Mercator map projection).