Tuesday, August 11, 2015

Landsat Maps Our Changing World

The Landsat program has been capturing satellite imagery of the Earth since the early 1970's. This means we now have access to over 40 years of satellite imagery, which is a wonderful resource for documenting changes to our planet.

Landsat Lens allows you to explore how the Earth has changed by allowing you to compare Lansat satellite imagery from six different years. The map allows you to search for any location on Earth and then overlay satellite imagery of your selected location from 1975, 1990, 2000, 2005, 2010 & 2015.

For example the screenshot above shows a map of the Aral Sea with four different satellite images from four different decades. Being able to directly compare the satellite images from different decades really helps to highlight the scale of how quickly the Aral Sea is disappearing.

Welcome to Fabulous Las Vegas (While Water Supplies Last) is a great visualization of the development of Sin City as seen from space. To create this animated map of Las Vegas' growth ProPublica processed 40 years of Landsat imagery.

The purpose of the map is to show how the city's water consumption has grown in conjunction with the city's expanding footprint. If you use the timeline beneath the map you can animate through the satellite images and see how the city has spread further and further out into the surrounding desert. Check-out how Lake Mead in particular seems to have visibly shrunk in size in just the last decade.

The map was created as part of ProPublica's superb Killing the Colorado interactive, which explores how man is engineering the death of this great American river.

You can also explore the rapid growth of Las Vegas over time on Time's Timelapse map. Timelapse allows you to create a timelapse sequence from satellite images (from 1984 to 2012) for anywhere on Earth.The application comes with a number of default views that allow you to view timelapse animations of satellite images showing the sprawling growth of Las Vegas, the building of Dubai, the shrinking of the Mendenhall Glacier and the drying-up of Lake Urmia.

Timelapse can be a little hard to navigate. You need to scroll down the page a little until the 'Explore the World' link appears in the header element at the top of the page. Click on the 'Explore the World' link and you can then choose from any of the default satellite animations or search for any location in the world.

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