Maine and Landsat: How Satellite Images Serve Forests, Fisheries, Farms and Coasts

Landsat satellites have imaged Earth's land surface for about 50 years — the longest continuous record of its kind. In Maine, that record helps manage forests, fisheries, farms and the coast.

Forests

With 89% of its territory in forest, Maine is the most forested state in the nation, and the forest industry, with an annual economic impact of $8.5 billion, drives the state's economy. Combined with county-level Forest Inventory and Analysis estimates, Landsat's time series lets decision makers analyze where forests are, detect loss from harvests, fire, disease and other disturbances, and track regrowth.

Landsat images of northeastern Maine from the summers of 1985, 2002 and 2019 (left to right). Green is forest; pink in the upper center and upper right is farmland; pink patches across the lower and middle parts of the images are forest that has been cleared. U.S. Geological Survey.

Fishing and farms

• Aquaculture. Each summer Maine closes parts of its coast to shellfish harvesting because of harmful algal blooms. University of Maine researchers showed that Landsat 8's validated temperature and water-quality data can help locate promising oyster farm sites out of harm's way.
• Agriculture. Landsat surface reflectance data can help tell nutrient shortages apart from insect or weed problems in fields. Farming guided by site-specific data can raise income, ease environmental problems and simplify management decisions.

Coasts and wetlands

Rising seas erode Maine's wetlands and beaches and increase storm damage. Geographers and remote-sensing scientists use Landsat to map shorelines and show decision makers:

• where filling tidal wetlands harms bird and fish habitat and removes a natural defense against coastal flooding;
• where storm surges are rising, eroding shorelines and leaving coastal cities more exposed;
• where highways, rail lines, wastewater plants and other infrastructure are threatened by sea-level rise and future surges.

Landsat and the nation

The USGS National Land Imaging Program supplies satellite imagery and other remotely sensed data to government, business, universities and the public, with worldwide access to Landsat through the USGS Earth Resources Observation and Science (EROS) Center.

Landsat is the most widely used source of land remote sensing data among federal civilian agencies. Local, state, tribal and federal agencies use it to monitor and forecast changes on the land surface, informing daily decisions about land, water and resources that protect life and property, safeguard the environment, advance science and education, support resilience to climate change and grow the economy. Businesses use it to improve logistics and investment decisions, and commercial imaging firms build services on it. A 2017 USGS study put Landsat's total annual economic benefit to the United States at $2.06 billion, far more than it costs to build and run.

Landsat 8 and Landsat 9 together image Earth's land every 8 days, and NASA and the USGS are planning Landsat Next to follow Landsat 9. With consistent, accurate data offered at no cost, and new cloud computing and analytics tools, Landsat — like GPS and weather data — is used every day to understand a changing planet.

Sources

• U.S. Geological Survey: "Maine and Landsat," Fact Sheet, citing Sader and others (2005), Snyder and others (2017), Leslie and others (2017), Pearsall (2021) and Straub and others (2019).