Science

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Today, for example, agricultural producers take for granted the ability to track and measure the Normalized Difference Vegetation Index (NDVI) values of the crops in their fields. Fifty years ago, the notion of tracking crop health from space was a distant dream, if pondered at all.

NDVI is measurement of crop health (greenness) built from a mathematical equation that factors in visible and near infrared light reflected from the Earth’s surface. It’s just one of several vegetation indices made possible by the recording of reflected light in the near infrared portion of the electromagnetic spectrum—something every Landsat satellite since 1972 has done, and something that simply wasn't possible prior to the land remote sensing era. The Multispectral Scanner (MSS) onboard the first Landsat marked the first time a civilian satellite recorded repeat, near-infrared information at the global scale.

Landsat was the driving force behind the first space-based global crop assessment project in the 1970s. Today, geospatial information system (GIS) software applications—even online-only tools for satellite data viewing—often allow users to calculate NDVI values with the click of a button, using data from Landsat or a host of other satellite sources for which visible and near-infrared data collection is standard. 

Landsat imagery also serve as the backbone of another agriculture tool producers in the U.S. now take for granted: the U.S. Department of Agriculture's Cropland Data Layer (CDL), which tracks crop types across the U.S. 

The program’s contributions to agriculture, of course, represent just one of countless examples of the ways the longest continuously collected satellite data source in history has improved our understanding of our planet’s form and function over the past 50 years.

The first National-scale land cover maps, the land cover and fuel-mapping information made available by the LANDFIRE program, global forest health monitoring, and much, much, more owe their existence to the Landsat program and its consistent, reliable record of the Earth's surface.

Click the “Societal Benefits,” “Stories,” and “Innovations” tabs at your left to explore just a few of the examples of how Landsat has improved our understanding of Earth.