Dear User,

The National Land Cover Data (NLCD) for some of the states available at the FTP site have not yet been assessed for accuracy. Those states that have been assessed for accuracy are shown in green on the previous page. You may see the results of the accuracy assessments at http://landcover.usgs.gov/accuracy/ . No datasets will be revised based upon the results of the accuracy assessments and the data on the FTP site are considered 'final'.

NO warranty is expressed or implied regarding the utility of these data.

The NLCD for each state is offered as an 8 bit flat binary file (*.bin.gz) or as a Geo-TIFF (*.tif.gz)

Important Data Limitations:

These data can be used in a geographic information system (GIS) for any number of purposes such assessing wildlife habitat, water quality, pesticide runoff, land use change, etc. However, the user must have a firm understanding of how the datasets were compiled and the resulting limitations of these data.

The National Land Cover Dataset was compiled from Landsat satellite TM imagery (circa 1992) with a spatial resolution of 30 meters and supplemented by various ancillary data (where available). The analysis and interpretation of the satellite imagery was conducted using very large, sometimes multi-state image mosaics (i.e. up to 18 Landsat scenes). Using a relatively small number of aerial photographs for 'ground truth', the thematic interpretations were necessarily conducted from a spatially broad perspective. Furthermore, the accuracy assessments correspond to 'federal regions' that are groupings of contiguous states. Thus, the reliability of the data is greatest at the multi-state or state level. The statistical accuracy of the data is known only for the region.

With this in mind, users are cautioned to carefully scrutinize the data to see if they are of sufficient reliability before attempting to use the dataset for larger-scale or local analyses. This evaluation must be made remembering that the NLCD represents conditions in the early 1990s.

The following link will take you to our FTP site. You will need to download at least two files, maybe three. One is the landcover data. It is available in two forms 1) a compressed 8 bit binary file (for example delaware_NLCD.bin.gz) or, 2) a compressed Geo-TIFF (Delaware_NLCD.tif.gz). These are raster datasets not vector. The second file you need is the documentation. Again this information is available in two forms 1) Federal Geographic Data Committee (FGDC) compliant metadata (delaware_FGDC.txt) or 2) delaware_readme.txt. These files contain projection and other important information. Lastly, you might want to download either flat2erdas.txt or flat2grid.txt. The first describes how to ingest the binary file into ERDAS Imagine. The second describes how to ingest the binary file into ARC/GRID or ARC/VIEW.

The Land Cover Program at the USGS EROS Data Center would like to invite you to become a registered user of the National Land Cover Dataset (NLCD). Providing the requested information will help us understand our customer's applications and improve the next national land cover product (NLCD 2001). We will also be able to inform you of new developments (accuracy assessments, updates, etc.)
Please Click Here to register as an NLCD user.

To retrieve the data go to the following URL:

http://edcftp.cr.usgs.gov/pub/data/landcover/states

Right click on the file you want and then save 'target' or 'link' as..... (Be sure the .gz extension is part of downloaded file name (*.bin.gz)).

Lastly, there are two text files which show the red/green/blue values to use to replicate the new USGS landcover colors. They are 'nlcd_colors_1.txt' and 'nlcd_colors_255.txt.' The '255' refers to RGB values in the range of 0-255 and the '1' refers to values in the range of 0-1.

To get a free viewer (DLGV32) to display the Geo-TIFF go to:

http://mcmcweb.er.usgs.gov/drc/dlgv32pro/