In honor of the 40th anniversary of the Landsat satellite imaging system that's been taking pictures of earth from space since 1972, the good folks at the National Aeronautics and Space Administration and the U.S. Geological Survey recently released a big set of images showing how the planet has changed over those four decades. Included in this birthday package was this nice set of images showing how 11 different cities around the world have changed in recent years. To help celebrate, we converted some of those time-separated images of cities into these 11 animated GIFs. It was quite the party.
Well, the internet overlords at Google have dealt our measly two-frame animations a big one-up. They've managed to import a huge chunk of that Landsat imagery into their Google Earth Engine, allowing users to move back and forth to any year between 1999 and 2011 on literally any spot on the map. They've even set it up so that users can watch a time-lapse animation of these 13 years of imagery for any place, zoomed in to almost any vantage point a map nerd could desire. This "time-explorable" map can only be viewed in the Chrome and Safari web browsers, but that shouldn't be too much of a barrier. (To get at it, have to go to Google Earth Engine, click through to one of the featured galleries like the Las Vegas time-lapse video, and a link will appear below taking you to the map if you are using Safari or Chrome).
In the video below, Bruce Pengra of the United Nations Environment Programme's Global Resource Information Database explains how Landsat imagery can show the dramatic urban changes that have happened in recent years, focusing on Las Vegas.
It's an interesting look at one city, but also shows how this fancy time-lapse map can give users a very visual understanding of change over time. The map has only 13 years of Landsat's 40 years of imagery, but that's still pretty incredible. It's a phenomenal piece of work, and one that will be sure to entertain and intrigue anyone interested in maps and change over time.