Landsat 7

Landsat, a joint program of the USGS and NASA, has been observing the Earth continuously from 1972 through the present day. Today the Landsat satellites image the entire Earth's surface at a 30-meter resolution about once every two weeks, including multispectral and thermal data. The USGS produces data in 3 categories for each satellite (Tier 1, Tier 2 and RT). Read more about the different tiers.

Surface Reflectance

Atmospherically corrected surface reflectance from the Landsat 7 ETM+ sensor.

Dataset Availability: January 1999 - Present

Top of Atmosphere

Landsat 7 ETM+ Collection 1 calibrated top-of-atmosphere (TOA) reflectance.

Dataset Availability: January 1999 - Present

Raw Images

Landsat 7 Collection 1 images, representing scaled, calibrated at-sensor radiance.

Dataset Availability: January 1999 - Present

Derived Datasets

Burn Area Index (BAI)

The Burn Area Index (BAI) is generated from the Red and Near-IR bands, and measures the spectral distance of each pixel from a reference spectral point (the measured reflectance of charcoal). This index is intended to emphasize the charcoal signal in post-fire images.

Enhanced Vegetation Index (EVI)

The Enhanced Vegetation Index (EVI) is generated from the Near-IR, Red and Blue bands of each scene, and ranges in value from -1.0 to 1.0.

Normalized Difference Vegetation Index (NDVI)

The Normalized Difference Vegetation Index is generated from the Near-IR and Red bands of each scene as (NIR - Red) / (NIR + Red), and ranges in value from -1.0 to 1.0.

Normalized Burn Ratio Thermal (NBRT)

The Normalized Burn Ratio Thermal (NBRT) index is generated from the Near-IR, Mid-IR (2215 nm), and Thermal bands, and has a range from -1.0 to 1.0. See Holden et al. (2005) for details.

Normalized Difference Snow Index (NDSI)

The Normalized Difference Snow Index is used to identify snow, based on its characteristically higher reflectance in the visible portion of the spectrum compared to the mid-IR. NDSI is computed using the Green and Mid-IR bands, and has a range of -1.0 to 1.0. See Riggs et al. (1994) for details.

Normalized Difference Water Index (NDWI)

The Normalized Difference Water Index (NDWI) is sensitive to changes in liquid water content of vegetation canopies. It is derived from the Near-IR band and a second IR band, ≈1.24μm when available and the nearest available IR band otherwise. It ranges in value from -1.0 to 1.0. See Gao (1996) for details.