National Land Cover Dataset
Overview | Public Availability | NCSU Access | Related Resources
2001 NC National Land Cover Database (NLCD) Raster.
Note to North Carolina data users: Please be aware of the existence of the 1996 Land Cover data, see: Detailed Data Listing. Other land cover options are listed in Related Resources.
Overview
The Original National Land Cover Database was created in 1992 by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC is in the process of creating a 2001 National Land Cover Database. Data for 1992 and 2001 are available for North Carolina. See the Availability section below for details.
Product description from USGS: "Derived from the early to mid-1990s Landsat Thematic Mapper satellite data, the National Land Cover Data (NLCD) is a 21-class land cover classification scheme applied consistently over the United States. The spatial resolution of the data is 30 meters and mapped in the Albers Conic Equal Area projection, NAD 83. The NLCD are provided on a state-by-state basis. The state data sets were cut out from larger 'regional' data sets that are mosaics of Landsat TM scenes. At this time, all of the NLCD state files are available for free download as 8-bit binary files and some
states are also available on CD-ROM as a Geo-TIFF. "
Processing overview from USGS: "The TM multi-band mosaics were processed using an unsupe"rvised clustering algorithm. Both leaves-off and leaves-on data sets were analyzed. The resulting clusters were then labeled using aerial photography and ground observations. Clusters that represented more than one land cover category were also identified and, using various ancillary data sets, models developed to split the confused clusters into the correct land cover categories. Click here for a more detailed discussion of the mapping and classification procedures."
"A hierarchical land cover classification scheme of 21 classes was developed and applied in a consistent manner across the entire United States."
The 21-class National Land Cover Data Key may be found online at: http://landcover.usgs.gov/classes.php
Background from USGS: "The National Land Cover Characterization project is part of the interagency Multi-Resolution Land Characterization (MRLC) initiative involving three divisions of the US Geological Survey (National Mapping Division, Water Resources Division, and the Biological Resources Division), the Environmental Protection Agency, the National Oceanic and Atmospheric Administration, and the US Forest Service. These agencies have a requirement for a nationally consistent land cover data set, and in 1993 these agencies combined financial resources to purchase Landsat Thematic Mapper data covering the entire United States. The USGS/EROS Data Center took the lead to process the data and develop the National Land Cover Data (NLCD) set. Procedures to evaluate the accuracy of the final product have been developed, and private contractors are completing accuracy assessments."
See also: Land Cover Characterization Project
Public Availability
1992 NLCD Availability: The entire coterminous U.S. is downloadable. GeoTIFF data for the eastern U.S. is available on CD-ROM at DH Hill Library.
2001 NLCD Availability: As of Summer 2005, only certain areas of the United States are available. This includes North Carolina.
The best public source for acquiring both of these data rasters is the USGS Seamless Data Distribution System.
NCSU Data Access
North Carolina
2001 and 1992 North Carolina Data is available on the Geodata Server at: /fedgov/usgs/landcov or ftp://geodata.lib.ncsu.edu/fedgov/usgs/landcov/ (by FTP) with accompanying metadata and layer files. See the Detailed Data Record for the 2001 data.
Eastern U.S.
1992 data for other eastern U.S. states is available on CD-ROM (G3701 .A4 1992 .G46) in the GIS Cabinet, DH Hill Reference Area. Data can also be made available for FTP upon request to Data Services. The following image shows data organization by CD-ROM:
Related Resources
USGS Land Use/Land Cover (LULC)
1998-99 EPA Neuse Basin Land Cover/Land Use
Landsat 7 Satellite Imagery (1999-2000)
SPOT Satellite Imagery (1993-1996)
Digital Orthophotography
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