The U.S. Geological Survey (USGS) released a newly updated and improved National land Cover Database (NLCD), known as Annual NLCD, which offers insights into the changing characteristics of landscapes across the U.S. from 1985 to 2023.
The updated land cover database now offers data starting in 1985 and in one-year increments. This is an improvement over the previous NLCD, which only mapped land cover from 2001 to 2021 and in two- to three-year increments.
The shift to Annual NLCD means scientists and resource managers will now have access to more timely and consistent land cover data, enabling them to track changes and trends at a finer time scale.
This improved frequency of updates will support environmental modeling, more accurate monitoring of land cover dynamics and better decision making for conservation and resource management.
“These improvements are the result of two years of research and development with the science user community’s evolving needs for land cover data in mind, so we anticipate a lot of interest,” USGS Research Geographer Jesslyn Brown said in a press release. “Over the summer, we processed more than 1.4 million Landsat observations and touched almost 300 trillion Landsat pixels to construct this land cover database.”
The NLCD project is a joint effort between the USGS and a group of federal agencies known as the Multi-Resolution Land Characteristics (MRLC) Consortium. The group ensures that land cover information is consistent and relevant at the national scale, which can make it invaluable for a variety of environmental, land management, and modeling applications.
The Annual NLCD features six new products
The latest dataset incorporates assessments and projections into six new products, which will now be released on an annual basis:
- Land Cover – This dataset provides 16 land cover classes such as deciduous and evergreen forest, grassland, cultivated crops and developed.
- Land Cover Change – These data represent annual land cover changes from one year to the next.
- Land Cover Confidence – This layer provides confidence levels for the land cover classifications.
- Fractional Impervious Surface – This component provides the proportion of land covered by developed surfaces, such as roads and rooftops.
- Impervious Descriptor – This feature offers additional information about impervious surfaces by distinguishing between roads and other built surfaces.
- Spectral Change Day of Year – This attribute captures the specific day of the year when significant changes in surface reflectance occur.
To ensure the reliability of these data, the USGS conducts a rigorous accuracy assessment, reviewing thousands of 30-meter plots annually to classify land cover and validate the data.
The NLCD data leverage the extensive Landsat satellite data record at a 30-meter resolution going back to the early 1980s.
NLCD supports thousands of applications in the private, public, and academic sectors. It has been used to assess ecosystem status and health, examine spatial patterns of biodiversity, understand climate change, and develop land management policies.
It also serves as a critical data layer in national assessments of surface and ground water quality, wildfire monitoring and modeling, urban heat risk, biological carbon sequestration, biodiversity conservation efforts and more.
