Monday, January 26, 2015

The Landsat Download Map

Libra is a new map tool from Development Seed and Dauria Geo which allows you to browse, find and download satellite imagery. Using Libra you can search and sort open Landsat data by date, location and cloud cover. Find some satellite imagery that you like and you can download it and use it in your own maps.

Libra provides a really neat and easy to use interface for sorting and downloading from more than 275 Terabytes of open Landsat imagery. There are no restrictions on the use of Landsat open data and it can be used or redistributed as you require. Each circle on the Libra map represents the number of available images at that location. You can filter the available images by date, cloud cover percentage and by sun azimuth angle.

The World Flag Map

World Flags is a CartoDB map in which the shape of every country had been overlaid with the country's flag. This patchwork effect appears to have been made by creating a polygon for each country and then filling the polygon with the correct flag image.

The flag polygons are themselves overlaid on top of Stamen's Watercolor map tiles.

Last year the Van Gogh Map also used images for land areas on a world map. This map was created with Mapbox GL (it therefore needs a WebGL enabled browser to view) and uses a different technique to fill in the land areas on the map.

Feature types on this map, such as water and different types of land cover, are made up of map tiles created with textures taken from Van Gogh paintings. The result is a map style which you probably wouldn't want to use very often but is a neat demo of how easy it is to create interesting map styles with Mapbox GL.

Mapping Traffic Density

Mapbox has created a map visualizing the latest Highway Performance Monitoring System national highway dataset. The Open US Highway Dataset Map shows all the HPMS traffic density measurements for US roads.

Roads on the map with traffic density data are colored yellow. The thickness of the yellow linea on the map relate to the amount of traffic. Thick lines indicate more traffic and thinner lines less traffic. Zoom in on the map and you can view the average number of vehicles per day for different sections of roads.

2004 Tsunami - Then & Now

Boxing Day 2004 Tsunami: Then and Now is an Esri map which allows you to compare satellite imagery taken immediately after the 2004 tsunami in the Indian Ocean with satellite imagery taken ten years later.

The 2004 Indian Ocean tsunami caused the deaths of over 230,000 people. This Esri map highlights the redevelopment of five of the worst affected areas using the Esri Story Map Swipe and Spyglass library. The swipe function allows you to directly compare two maps of the same area by dragging either map over the top of the other.

This tsunami map allows you to directly compare 2004 satellite imagery of Indonesia, Sumatra, Sri Lanka and Thailand with imagery captured in 2014.

Sunday, January 25, 2015

Maps of the Week

This month Tommy Caldwell and Kevin Jorgeson became the first climbers to free-climb the 3,000-foot Dawn Wall of El Capitan. The New York Time's The Dawn Wall interactive is an impressive 3d model of their route up the mountain, created by Battista Matasci of the University of Lausanne..

Open The Dawn Wall in a WebGL enabled browser and you can follow Caldwell and Jorgeson's climb on an interactive 3d model of the Dawn Wall. As you scroll down the interactive the model rotates and zooms with impressive speed. Photos and information about the climb can be viewed as you progress along the climbers' route.

Mapbox has released a gorgeous map of all the roads in Japan. OpenStreetMap in Japan only shows Japan's roads and streets and omits all over map features.

The roads on the map are colored by the last date that they were edited on OpenStreetMap. Roads colored blue haven't been edited since 2007. The yellow roads have been edited in the past year. The Mapbox post on the map includes a link to a full-screen map. The map embedded in the post however includes a button to quickly toggle to view close-ups of major cities on the map.

Sailing Seas of Plastic is an interactive mapped visualization of the concentration of plastic in the world's oceans. According to the map there are 5,250 billion pieces of plastic, with a combined weight of 268,940 tonnes, adrift on the seas of the world.

This dot density map shows the estimated concentration of floating plastic in the oceans. Each dot on the map represents 20 kg of floating plastic. The estimations are based on the results of 24 survey expeditions (2007-2013) and on wind and ocean drift models.

You can also overlay the sailing tracks of the 24 survey expeditions on top of the dot map.

The European River Map

Earlier this month Andrew Hill created a beautiful looking map of U.S. Rivers Colored by the Direction they Flow. Europeans now have their own river flow map.

Rivers of Europe is a CartoDB map showing only European rivers. The map uses the same color scheme as Andrews' US rivers map so I assume that the European map also colors each river by its direction of flow. If you click on the 'Datasets used in this map' you see the data used in the map. The data includes a column for 'bearing' so it is likely that that the rivers are colored by their direction of flow.

Saturday, January 24, 2015

How to Create Interactive Vintage Maps

Today I was going to sit down and write a tutorial on how I created the New York Vintage Map using Leaflet.js and old historical map tiles from the New York Public Library. However I saved myself a couple of hours of work when I came across this excellent tutorial From Paper Maps to the Web on the library's own NYPL Labs site.

The tutorial is a step-by-step guide explaining how to create an interactive map from one of the New York Public Library's vintage maps using Leaflet.js. Before looking at the tutorial have a look at the finished map, Mapa. The map is a 1891 map of Bogotรก, Colombia overlaid with pop-ups containing information about some of the city's prominent politicians at the time (mapped to their home addresses).

The NYPL tutorial was written by Mauricio Giraldo Arteaga. By some strange coincidence Mauricio has also been playing around with some of the same vintage maps of Lower Manhattan which I used in my New York Vintages Maps collection.

His ScrollNYC is a visualization of vintage New York city maps from 1660 through to 1921. Each of the historical maps has been overlaid on top of a static Mapbox modern map of New York. As you scroll down the page each static map is replaced by an older map in reverse chronological order.

Dynamic Driving Directions with Turf

Turf is now available as a Mapbox.js plugin and can be used to perform many common GIS operations. Over the last few weeks the Mapbox blog has been posting a number of interesting examples of how Turf can be used with the Mapbox platform:

Dynamic walkability estimation with Turf
Find your nearest cup of coffee with Turf
Turf for local gov: potholes and parking meters
Analyzing 60 years of tornadoes with Turf

The posts on the Mapbox blog provide a number of useful use cases of how Turf can be deployed with Mapbox and provide some useful tips for anyone who is looking to develop a Mapbox based map using the Turf plug-in.

On Thursday Mapbox posted a very nice example of using Turf with Mapbox driving directions. Keep on truckin' with Turf.js and Mapbox Directions animates a marker along a route from San Francisco to Oakland.

As the marker follows the driving route all the nearby electric vehicle charging stations are automatically added to the map using Turf's .distance() method. You can test how fast Turf can process data on the fly by dragging the start and end destination markers on the map to create a new route. Change the route and you can see how the nearby electric vehicle charging stations are updated instantly on the map.

As the animated marker follows a route you can also select any of the charging station markers on the map. The route is then automatically updated to take in a stop at the selected charging station.

Friday, January 23, 2015

Mapping Olde New York

Having used the New York Public Library's map collection to put together a little Leaflet.js map of New York Vintage Maps I remembered that the library also has a great collection of free and open access vintage photographs. I therefore decided to take advantage of the library's collection of historical photographs of New York to add some vintage photos of Lower Manhattan to the vintage maps of New York.

My New York Vintage Maps site therefore now displays vintage maps which have been georectified by the New York Public Library's Map Warper project overlaid with old photos (and one or two sketches) from the New York Public Library's Digital Collections.

My New York Map is obviously inspired by other great vintage map and photographs sites such as Our Town Stories - Edinburgh and Helsinki Ennen. The Helsinki map includes the option to filter the maps and photos by decade, allowing you to view the historical photos of the city on a map from the same decade. In the future I hope to add a similar filter to the New York Vintage Maps collection.

The Road Less Traveled on Google Maps

The road less traveled is paved with Foursquare venues and plastered with Instagram photos. At least that seems to be the curious message behind Roadless. This new travel map's motto is,

"Don't trust the masses. Start wandering and build your road less travelled".

How should you explore the 'road less travelled'? That's right by exploring the photos and venues crowd-sourced for the world on location sharing and photo sharing websites such as Foursquare, Flickr and Instagram.

I'm not entirely sure that exploring travel destinations in this way is going to lead you to the less traveled areas of the world. However, this quibble aside, Roadless is an interesting way to explore potential places to visit. Zoom to a location on the Roadless map and you can view photos of the destination and potential venues to visit as listed on Foursquare.

The Roadless map is well worth exploring before visiting a location to scope out potential places to visit. If a photo or venue catches your interest on the map you can click on its map marker to view details of the venue, such as its address and opening hours. You can also select the 'Popular Nearby' tab to view other interesting places to visit in the same area.