Land Use & Land Cover Data
Introduction
Land Use and Land Cover (LULC) data refer to data that is a result of classifying raw satellite data into "land use and land cover“ classes.
Land Use is a description of how people utilize the land and of socio-economic activity. Land use shows how people use the landscape , whether it's developed, agriculture, or mixed uses.
Land Cover is the physical material on the surface of the earth. Land cover data documents how much of a region is covered by forests, wetlands, impervious surfaces, agriculture, and other land and water types.
Land cover data can help us better understand the landscape and how humans are using it. LULC maps can help us examine urban growth, changing land cover and predict and assess impacts from climate change. Historical LULC datasets help in assessing changing land use and over time. Most LULC data is in a raster format. Sometime LULC data is available in vector format, but the file sizes can be very large.
National Land Cover Database (NLCD)
The National Land Cover Database (NLCD) provides nationwide land cover data. The land cover data is based on 30-meter resolution Landsat data. as the definitive Landsat-based, 30-meter resolution, database for the Nation. The land cover data supports a wide variety of Federal, State, local, and nongovernmental applications that seek to assess ecosystem status and health, understand the spatial patterns of biodiversity, predict effects of climate change, and develop land management policy. NLCD products are created by the Multi-Resolution Land Characteristics (MRLC) Consortium, a partnership of Federal agencies led by the U.S. Geological Survey.
Data
Land Use and Land Cover
The MRLC pooled their resources to purchase Landsat data and create a national land cover database in the early 1990s. The first national NLCD data was released in 1993 and represented the land cover as observed in 1992. The Consortium repeated this effort nearly a decade later to produce the NLCD 2001 data. The MRLC now strives to create this data with a 5-year cycle and has released a 2006, 2011 and 2016 (releasing in 2019) land cover dataset. All NLCD data products are available for download at no charge to the public from the MRLC Web site: http://www.mrlc.gov.
Land Cover Change
NLCD analysis of land cover change across the conterminous United States from 2001 to 2006 revealed that approximately 1.68 percent [135,560 square kilometers (km2)] of the total land area changed. The greatest proportion of change occurred in the Pacific Northwest and in the Southeast. Multiple land cover change products have been released, including changes from 1992 to 2011 and various intervals in between.
The above images show the land cover data from the Arcata area in 2006 and 2011. The right image shows the change from 2006 to 2011. The black areas haven't changed while the colored areas show the change to the most recent land cover type.Land Cover Trends is a USGS research project focused on understanding the rates, trends, causes, and consequences of contemporary U.S. land use and land cover change. The final report, Status and Trends of Land Change in the Western United States 1973-2000 covers 30 ecological regions in the Western United States and is the most detailed and comprehensive assessment of the rates and types of land-use and land-cover change ever produced for the region.
Tree Canopy Cover
In 2011, the United States Forest Service (USFS) developed the 2011 Tree Canopy Cover product of the National Land Cover Database (NLCD). The Tree Canopy Cover data consists of a single layer with percent tree canopy cover. File pixel values range from 0 to 100 percent, with each individual value representing the area or proportion of that 30m cell covered by tree canopy. This data is used for a variety of applications such as carbon estimation, wildlife habitat, and wildland fire purposes.
Percent Developed Impervious Surface
Percent Developed Impervious surface provides nationally consistent estimates of the amount of man-made impervious surfaces present over a given area. Like the other NLCD, these data sets are derived from Landsat satellite imagery using classification schemes. In this data values range from 0 to 100 percent, indicating the degree to which the area is covered by impervious features.