What Can You Do With 40 Years of Imagery?

A colleague recently pointed me to an interesting video on NASA’s YouTube page, cleverly titled “What Doesn’t Stay in Vegas? Sprawl.”  This video shows the rapid expansion of Las Vegas between 1972 and 2010.  The video comprises 38 years worth of color-infrared images from the Landsat satellites.  In these images, green vegetation, which is not naturally abundant in the Mojave Desert, shows up as bright red.

Color-infrared images of Las Vegas, collected by Landsat 1 in 1972, and by Landsat 7 in 2010.

Aside from being interesting and a bit appalling to watch, the video also illustrates one of the many reasons that it can be so valuable to have compatible remotely sensed data collected repeatedly over a long time period.  Data from the Landsat program is unparalleled in its ability to directly measure and illustrate change on the earth’s surface.  As NASA’s description of the video puts it:

“Landsat data have been instrumental in increasing our understanding of forest health, storm damage, agricultural trends, urban growth, and many other ongoing changes to our land resources. Studies using Landsat data have helped land managers keep track of the pace of urbanization in locations around the world.”