Can I Use the Latest USGS NLCD 2011 Land Use Data with TAP?

TAP6.1 release 2515 (and later), with a maintenance subscription of 01 August 2013 (and later), now supports the National Land Cover Database 2006 and 2011 land use data.  TAP 7 also supports NLCD 2011.

The previous TAP land use / land cover (LULC) data is circa 1992 and has a spatial resolution of 200 meters.

National Land Cover Database 2011 (NLCD2011) is a 16-class1 land cover classification scheme that has been applied consistently across the conterminous United States at a spatial resolution of 30 meters. NLCD2011 is based primarily on the unsupervised classification of Landsat Enhanced Thematic Mapper+ (ETM+) circa 2011 satellite data.

SoftWright has available NLCD 2011 data in 1-by-1 degree tiles, available for purchase individually, by state, geographic area, or the entire conterminous United States.

Each tile is a GeoTiff file in the Albers Conic projection. [While these tiles are viewable in any image viewer, some less-capable GIS software packages will not correctly combine the NLCD raster image with other rasters that use different projections.]

NLCD 2011 data is installed for the demo area when either the TAP6 demo or the TAP6 update (2515 or later) is installed. The following path study shows the 1992 LULC data from the demo area near Denver, CO, USA:

USGSLULC

This is the same path study using the NLCD 2011 data:

USGSNLCD

These studies clearly show the higher resolution of the NLCD data, as evidenced by thinner, more rapidly-changing land use bands.  The NLCD data also shows more urban areas (in orange) as one would expect after 20 years of development near Denver.

The NLCD data is integrated into TAP alongside the older LULC and GLC (Global Land Cover) data sets.  It is enabled by default in the TAP6 menu:

LandUseSettings

The land use path must be configured to contain the folder in which the NLCD tiles may be found, via the Land Use -> File Locations menu item (above).  The File Locations dialog, shown with the demo NLCD path:

NLCD_menu

To install your NLCD 2011 data, you may copy it to any path accessible by your system, or use it on the distribution media; you do not need to copy it into the demo LULC\Nlcd2011 folder.  You must, however, use the menu and dialog above to configure TAP to include the NLCD path.  If you already have TAP installed and are applying the update, and if your land use paths already have two or more entries, then the installer will not add the demo land use file path to your list of land use file paths.  You will need to manually do the addition using the “File Locations” menu item.  The demo folder is <installdir>\LULC\Nlcd2011.

When NLCD is configured, TAP will first try to use it for land use data, and then fall back to LULC and GLC, in that order, if no NLCD data is found for a given point.

Performance Tip:  If you are confident that you have NLCD coverage for your study, disabling LULC and GLC land use can decrease study calculation times by minutes, depending upon your devices and file organization.

The NLCD 2011 legend is below:

NLCD_Colour_Classification_Update

NLCD source:  http://www.mrlc.gov/nlcd11_leg.php

Citation: Fry, J., Xian, G., Jin, S., Dewitz, J., Homer, C., Yang, L., Barnes, C., Herold, N., and Wickham, J., 2011. Completion of the 2006 National Land Cover Database for the Conterminous United States, PE&RS, Vol. 77(9):858-864.

1 16 classes for CONUS.  Additional classes are reserved for Alaska and Hawaii.